As filed with the Securities and Exchange Commission on March 15, 2004

Registration No. 333-                

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ATMOS ENERGY CORPORATION

(Exact name of registrant as specified in its charter)

Approximate date of commencement of proposed sale to public:

From time to time after this registration statement becomes effective.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.   x

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.   ¨

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.   ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.   ¨

If delivery of the prospectus is expected to be made pursuant to Rule 434, please check the following box.   ¨

CALCULATION OF REGISTRATION FEE

PROSPECTUS

2,000,000 Shares

ATMOS ENERGY CORPORATION

DIRECT STOCK PURCHASE PLAN

Common Stock

We are offering the shares to our shareholders, our customers and other investors under our Direct Stock Purchase Plan. Plan participants may also take advantage of additional services, most without any fees or commissions.

Under our plan, participants may:

The shares trade on the New York Stock Exchange under the symbol “ATO.” On March 11, 2004, the last sale price of the shares as reported on the New York Stock Exchange was $25.94 per share.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is March 15, 2004.

We have not authorized any other person to provide you with any information or to make any representations not contained in this prospectus. If anyone provides you with different or inconsistent information, you should not rely on it. We are not making an offer of any securities other than the shares. You should assume that the information appearing in this prospectus, as well as the information contained in any document incorporated by reference, is accurate as of the date of such document only.

 
TABLE OF CONTENTS

The distribution of this prospectus, and the offering of the shares, may be restricted by law in certain jurisdictions. You should inform yourself about, and observe, any of these restrictions. This prospectus does not constitute, and may not be used in connection with, an offer or solicitation by anyone in any jurisdiction in which the offer or solicitation is not authorized, or in which the person making the offer or solicitation is not qualified to do so, or to any person to whom it is unlawful to make the offer or solicitation.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the Securities and Exchange Commission under the Securities Exchange Act of 1934. You may read and copy this information at the Public Reference Room of the SEC, 450 Fifth Street, N.W., Room 1024, Washington, D.C. 20549, at prescribed rates. You may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330.

The SEC also maintains an Internet website that contains reports, proxy statements and other information about issuers, like us, who file electronically with the SEC. The address of that Website is www.sec.gov.

You can also inspect reports, proxy statements and other information about us at the offices of the New York Stock Exchange, Inc., 20 Broad Street, New York, NY 10005.

We have filed with the SEC a registration statement on Form S-3 that registers the shares of common stock we are offering. The registration statement, including the attached exhibits and schedules, contains additional relevant information about us and the shares of common stock being offered. The rules and regulations of the SEC allow us to omit certain information included in the registration statement from this prospectus.

INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” information into this prospectus that we have filed with it. This means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be a part of this prospectus, except for any information that is superseded by information that is included directly in this document. We incorporate by reference the documents listed below and any additional documents we may file with the SEC under sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934 prior to the termination of our offering of securities. These additional documents include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K (other than filings under items 9 or 12), as well as proxy statements.

This prospectus incorporates by reference the documents listed below that we have filed with the SEC but have not included or delivered with this document. These documents contain important information about us and our financial condition.

You may obtain a copy of any of these filings from us without charge by requesting it in writing or by telephone from us at the following address or telephone number:

Atmos Energy Corporation

1800 Three Lincoln Centre

5430 LBJ Freeway

Dallas, Texas 75240

Attention: Shareholder Relations

(972) 934-9227

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

Statements contained in this prospectus that are not statements of historical fact are “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933. Forward-looking statements are based on management’s beliefs as well as assumptions made by, and information currently available to, management. Because such statements are based on expectations as to future economic performance and are not statements of fact, actual results may differ materially from those stated. Important factors that could cause future results to differ include, but are not limited to:

All of these factors are difficult to predict and many are beyond our control. Accordingly, while we believe these forward-looking statements to be reasonable, there can be no assurance that they will approximate actual experience or that the expectations derived from them will be realized. When used in our documents, the words “anticipate,” “believe,” “estimate,” “expect,” “objective,” “projection,” “plan,” “forecast,” “goal,” “seek,” “strategy” or similar words are intended to identify forward-looking statements. We undertake no obligation to update or revise our forward-looking statements, whether as a result of new information, future events or otherwise. For further discussion of these factors, please refer to the Management’s Discussion and Analysis of Financial Condition and Results of Operations in our Annual Report on Form 10-K for the year ended September 30, 2003 and our Quarterly Report on Form 10-Q for the three months ended December 31, 2003.

PROSPECTUS SUMMARY

You should read the following summary in conjunction with the more detailed information contained elsewhere in this prospectus and the documents incorporated by reference in this prospectus.

Upcoming Plan Changes

We are making several changes to our Direct Stock Purchase Plan that will become effective on April 1, 2004. The most important of these changes are:

The descriptions of our Direct Stock Purchase Plan in this prospectus reflect these and other changes that will become effective on April 1, 2004. However, in each instance where a change to the plan is reflected, we have inserted a notation to reflect the terms and conditions of the plan that will be in effect only through March 31, 2004.

The Plan

We offer our Direct Stock Purchase Plan to provide our shareholders, our customers and other investors with a convenient and economical way to purchase our common stock and accumulate and increase their investment in our common stock by reinvesting all or a portion of their cash dividends in additional shares. We currently do not charge any service fees or brokerage commissions on any purchases of common stock under the plan.

The plan administrator will use reinvested dividends, initial investments and optional cash investments it receives from participants to buy shares of our common stock for those participants through the plan at then current market prices, as discussed in more detail below. The plan administrator may buy shares on the market from brokers or may buy shares directly from us.

The Offering

This prospectus relates to 2,000,000 authorized shares of our common stock offered for purchase under the plan by shareholders and other investors through initial investments, the reinvestment of dividends and optional cash investments of at least $25 and not more than $100,000 per calendar year. Non-shareholders must make initial investments of at least $1,250 ($200 through March 31, 2004) and not more than $100,000. Shareholders are not required to make initial investments if they own of record at least 50 shares of our common stock (one share through March 31, 2004). Beginning April 1, 2004, any shareholder who does not own of record at least 50 shares of our common stock must make an initial investment of at least $1,250 and not more than $100,000 to participate in the plan.

All shares purchased with initial investments, reinvested dividends or optional cash investments, including automatic monthly investments, are purchased at then current market prices. (However, shares purchased with reinvested dividends through March 31, 2004, are offered at a 3% discount from then current market prices, subject to a limit of reinvested dividends paid quarterly on the participant’s first 40,000 shares held in the plan.) A participant may make no more than $100,000 of optional cash investments during any calendar year, and a non-participant may not make an initial investment of more than $100,000. However, after an initial investment is made, a participant is allowed to make optional cash investments up to $100,000, including the initial investment, during that and each subsequent calendar year.

The terms “we,” “our” and “us” refer to Atmos Energy Corporation unless the context suggests otherwise. The term “you” refers to an existing plan participant or a prospective plan participant.

ATMOS ENERGY CORPORATION

We and our subsidiaries are engaged primarily in the natural gas utility business, as well as certain non-utility businesses. We distribute natural gas through sales and transportation arrangements to approximately 1.7 million residential, commercial, public authority and industrial customers through our six regulated utility divisions, which cover service areas located in the following 12 states: Colorado, Georgia, Illinois, Iowa, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Tennessee, Texas and Virginia. In addition, we transport natural gas for others through our distribution system.

Through our non-utility businesses, we provide natural gas management and marketing services to industrial customers, municipalities and other local gas distribution companies in 18 states. We also supplement natural gas used by our customers through natural gas storage fields that we own or hold an interest in and which are located in Kansas, Kentucky, Louisiana and Mississippi. We market natural gas to industrial and agricultural customers primarily in west Texas and to industrial customers in Louisiana. We also construct electric power generating plants and associated facilities to meet peak load demands and lease or sell them to municipalities and industrial customers.

Our operations are divided into three segments:

Our principal executive offices are at 1800 Three Lincoln Centre, 5430 LBJ Freeway, Dallas, Texas 75240, our telephone number is (972) 934-9227, and our Internet website address is www.atmosenergy.com. Information on our Internet website is not part of this prospectus.

USE OF PROCEEDS

We do not know the number of shares that we will sell to the plan administrator under the plan nor the prices at which the shares will be sold. We will use the net proceeds we receive pursuant to this offering for general corporate purposes.

PLAN OF DISTRIBUTION

The shares are being offered pursuant to our Direct Stock Purchase Plan described in this prospectus. The plan administrator will purchase the shares being offered directly from us or on the open market, at our discretion. In accordance with current rulings by the Securities and Exchange Commission, we will not change our determination regarding the source of shares being purchased by the plan administrator under the plan more than once in any three-month period. Any change in the source of the shares being purchased will be made by a determination of our board of directors, a determination by our chief financial officer that we need additional capital, or a determination by us that there is another valid reason for a change. We generally pay all fees, commissions and expenses incurred in connection with the plan, including any annual administrative fee. However, a participant is responsible for all commissions and fees relating to the sale of all or a portion of the shares in his or her plan account.

DESCRIPTION OF THE PLAN

The following is a question and answer description of our Direct Stock Purchase Plan:

Purpose and Advantages

1.    What is the purpose of the plan?

The purpose of the plan is to provide to our shareholders, our customers and other investors a simple, convenient and economical way to accumulate and increase their investment in our common stock by reinvesting all or a portion of their cash dividends paid quarterly in additional shares of our common stock. However, shareholders using the plan for arbitrage, or short-term income producing strategies, may have their participation in the plan terminated by the plan administrator.

2.    What are some of the advantages of the plan?

Disadvantages of the Plan

3.    What are some of the disadvantages of the plan?

Administration

4.    Who administers the plan?

The plan administrator administers the plan, purchases and holds the shares acquired under the plan, maintains records, and sends statements of account activity to participants. All enrollment applications, optional cash investments, notices of withdrawal and termination and all other matters and communications related to the plan should be addressed to:

Atmos Energy Corporation

c/o American Stock Transfer & Trust Company

Dividend Reinvestment Department

P.O. Box 922

Wall Street Station

New York, NY 10269-0560

(Through March 31, 2004)

Atmos Energy Corporation

c/o EquiServe Trust Company, N.A.

Dividend Reinvestment Department

P.O. Box 43010

Providence, RI 02940-3010

Please mention Atmos Energy Corporation in all correspondence and provide your plan account number or social security number.

Participants may also telephone AST toll free at 1-800-543-3038, Monday through Thursday, 8:00 a.m.-7:00 p.m. Eastern Time, and Friday, 8:00 a.m.-5:00 p.m. Eastern Time (EquiServe toll free at 1-800-543-3038, Monday through Friday, 9:00 a.m.-6:00 p.m. Eastern Time, through March 31, 2004).

Beginning April 1, 2004, participants may also complete all transactions online at www.amstock.com.

Participation

5.    Who is eligible to participate in the plan?

Any person or entity, whether or not a holder of record of our common stock, is eligible to participate in the plan if (a) the person or entity fulfills the prerequisites for participation described below under “Enrollment Procedures,” and (b) in the case of citizens or residents of a country other than the United States, its territories and possessions, participation in the plan would not violate local laws applicable to us or the participant. Each participant in the plan will remain enrolled in the plan until he or she instructs the plan administrator in writing to close his or her account.

Participants in our Retirement Savings Plan are not eligible to participate in our Direct Stock Purchase Plan through the retirement plan. However, Retirement Savings Plan participants are eligible to participate in our Direct Stock Purchase Plan with respect to shares of our common stock held outside the Retirement Savings Plan if they meet the requirements for participation in our Direct Stock Purchase Plan.

Beginning April 1, 2004, participants will no longer be able to purchase shares through any IRA accounts, including traditional IRA, Roth IRA, Coverdell IRA and SEP-IRA accounts.

Enrollment Procedures

6.    How does a person participate in the plan?

7.    What does the enrollment application provide?

The enrollment application provides for the purchase of additional shares of our common stock by a shareholder of record through the following investment options:

Participants may elect to have cash dividends deposited electronically into a bank checking or savings account at no charge by completing a direct dividend deposit authorization form available from the plan administrator or online (not available through March 31, 2004).

A participant may elect to purchase shares through full or partial dividend reinvestment or optional cash investments only, and may change the number of shares subject to dividend reinvestment from time to time by completing and submitting to the plan administrator a new enrollment application. To be effective with respect to a particular dividend, any change in the reinvestment election must be received by the plan administrator on or before the record date for such dividend. It is not necessary for participants to hold shares in certificated form to receive cash dividends on all of their shares. However, beginning April 1, 2004, participants who choose to receive cash dividends on only a portion of their shares must hold such shares in certificated form.

8.    When may a person join the plan?

After reviewing a copy of this prospectus, non-shareholders of record may join the plan at any time by completing an enrollment application online (not available through March 31, 2004) or by mailing it to the plan administrator along with their initial investment of at least $1,250 ($200 through March 31, 2004). After reviewing a copy of this prospectus, eligible shareholders of record who own at least 50 shares (one share through March 31, 2004) may enroll in the plan at any time. Any investment received as an initial investment without a properly completed enrollment application will be returned and no action will be taken. If an enrollment application requesting reinvestment of dividends is received by the plan administrator on or before the record date for a dividend payment, then that dividend payment will be applied toward the purchase of shares of our common stock. Record dates are ordinarily the 25th day of February, May, August and November. However, when the 25th day of those months falls on a national holiday, then the dividend record date is the first business day following that holiday.  

If the plan administrator receives an enrollment application requesting reinvestment of dividends after the record date established for a particular dividend, then the reinvestment of dividends will begin on the dividend payment date following the next record date if that shareholder is still a holder of record.

Purchases and Price of Shares

9.    What is the source of stock purchased under the plan?

At our discretion, the plan administrator will purchase shares of our common stock either directly from us or on the open market. If the shares are purchased directly from us, they will be either authorized but unissued shares or shares held by us as treasury stock.

10.    When will shares be purchased under the plan?

The plan administrator will purchase shares directly from us on the relevant investment date. Purchases on the open market will begin on the relevant investment date and will be completed no later than 30 days from that date, except where completion at a later date is necessary or advisable under any applicable federal securities laws. These purchases may be made on the New York Stock Exchange or any other securities exchange where our shares of common stock are traded, in the over-the-counter market or by negotiated transactions, and may be subject to terms with respect to price, delivery and other terms as the plan administrator may agree. Neither we nor any participant will have any authority or power to direct the time or price at which shares may be purchased or the selection of the broker or dealer through or from whom purchases are to be made. When shares are purchased on the open market, participants become owners of the shares as of the date of settlement.

There are at least four investment dates each month. The investment dates are the first business day of each week, except for any week which contains a dividend payment date, in which event the dividend payment date will become the investment date. However, if the dividend payment date is on a Friday, the investment date will be the following business day. If an investment date falls on a date on which the New York Stock Exchange is closed, the first succeeding day on which the New York Stock Exchange is open will be the investment date.  

11.    What will be the price to the participant of shares purchased under the plan?

The purchase price of shares purchased under the plan will be determined as follows:

12.    How many shares will be purchased for participants?

The number of shares to be purchased depends on the amount of the participant’s dividends, if any, the share price, and any optional cash investments or initial investments received by the plan administrator. Each participant’s account will be credited with the number of shares, including fractions, equal to the total amount invested, divided by the purchase price.

Initial Investments and Optional Cash Investments

13.    How are initial investments made?

Initial investments must be at least $1,250 ($200 through March 31, 2004) and not more than $100,000. Initial investments may be made in the form of a check or money order, and must be included with the completed enrollment application form and returned to the plan administrator at the address listed on the form. Initial investments may also be made online (except for initial investments made through March 31, 2004).  

14.    How does the optional cash investment feature of the plan work?

All new investors and eligible shareholders of record who have submitted an enrollment application to the plan administrator online (not available through March 31, 2004) or by mail are eligible to make optional cash investments at any time. Payments may be made by check or money order or may be deducted electronically on a monthly basis from a financial institution account. All investments must be payable to the plan administrator in U.S. dollars and drawn against a U.S. bank. The plan administrator will not accept third party checks. The plan administrator will apply any optional cash investment or initial investment received from a participant to the purchase of shares of our common stock for the account of the participant on the next investment date, if the shares are purchased from us, or as soon as practicable on or after the next investment date, if the shares are purchased on the open market.

In the event that any check or automatic monthly investment is returned unpaid for any reason, the plan administrator will consider the request for investment of that money null and void and will immediately remove from the participant’s account shares, if any, purchased upon the prior credit of that investment. A reasonable fee, currently $25, will also be assessed against the participant’s account. The plan administrator will then be entitled to sell those shares to satisfy any uncollected amounts. If the net proceeds of the sale of those shares are insufficient to satisfy the balance of any uncollected amounts, the plan administrator will be entitled to sell additional shares from the participant’s account to satisfy the uncollected balance.

Brokers or nominees may not utilize any feature of the plan (except the dividend reinvestment feature of the plan through March 31, 2004). Accordingly, if a beneficial owner of shares wishes to participate in the cash investment features of the plan at any time or the dividend reinvestment feature of the plan at any time after March 31, 2004, that owner must become a record holder of at least 50 shares of our common stock (one share through March 31, 2004) by having all or part of his or her shares transferred to his or her name or make an initial investment of at least $1,250 ($200 through March 31, 2004).

Initial investments and optional cash investments received by the plan administrator no later than 12:00 Noon on the business day preceding an investment date will be held by the plan administrator and invested beginning on the investment date. No interest will be paid on amounts held by the plan administrator pending investment. After sending an initial investment or optional cash investment, if a participant changes his or her mind and decides he or she does not want to participate in the plan, then, upon a participant’s written request received by the plan administrator at least two business days prior to the applicable investment date, an initial investment or optional cash investment will be returned to the participant. However, no refund of a check or money order will be made until the funds have been actually received by the plan administrator and cleared by the bank or financial institution upon which the check has been written.

Expenses and Costs

16.    What are the costs to participants in the plan?

For plan participants, there are no brokers’ commissions and no fees or service charges in connection with purchases of shares. We pay these costs, along with any costs for administration of the plan. However, participants are charged a fee for selling shares through the plan.

Reports to Participants

17.    What reports will be sent to participants in the plan?

After each transaction in a participant’s account, the plan administrator will send to the participant a transaction confirmation showing the details of the transaction. Each participant will also receive a quarterly investment statement showing any amount invested by initial investment, any amounts invested by optional cash investments, any amounts invested using dividends, the purchase price and number of shares purchased and other information resulting from investment activity for the year to date. Each statement also contains a form that can be used to deposit shares for safekeeping, make optional cash investments or withdraw shares from the plan. At each year-end, the statement will include all information pertaining to a participant’s account for the year and should be retained for federal and state income tax purposes. Each participant will also receive copies of the same communications sent to every other holder of shares, including our Annual Report to Shareholders and our Notice of Annual Meeting and Proxy Statement. In addition, each participant will receive annually Internal Revenue Service information on Form 1099-DIV for reporting dividend income received.

Stock Certificates and Safekeeping

18.    What is the safekeeping feature of the plan and how does it work?

At the time of enrollment in the plan, or at any later time, participants may use the plan’s safekeeping service to deposit with the plan administrator stock registered in the name of the participant. Shares deposited will be transferred into the name of the plan administrator or its nominee and credited to the participant’s account under the plan. After that time, those shares will be treated in the same manner as shares purchased through the plan.

By using the plan’s safekeeping service, participants do not bear the risk associated with loss, theft or destruction of stock certificates. Also, because shares deposited with the plan administrator are treated in the same manner as shares purchased through the plan, they may be transferred or sold through the plan in a convenient and efficient manner. Dividends paid on shares deposited for safekeeping may be reinvested or paid in cash. Participants may elect to receive cash dividends on all or a portion of those shares by completing and submitting to the plan administrator a new enrollment application indicating the number of whole plan shares for which they choose to receive cash dividends. However, beginning April 1, 2004, participants who wish to receive cash dividends on only a portion of their shares must hold those shares in certificated form and submit to the plan administrator a new enrollment application indicating the number of certificated plan shares for which they choose to receive cash dividends.

The participant bears the risk of replacement costs if any certificates for shares are lost. Therefore, participants who wish to deposit their stock certificates with the plan administrator should consider sending them with a letter of direction to the plan administrator by registered mail, first class mail, or certified mail, return receipt requested, properly insured, to the following address:

American Stock Transfer & Trust Company

Dividend Reinvestment Dept.

P.O. Box 922

Wall Street Station

New York, NY 10269-0560

Certificates sent by overnight delivery service should be addressed to:

American Stock Transfer & Trust Company

Dividend Reinvestment Dept.

59 Maiden Lane, Plaza Level

New York, NY 10038

The stock certificates should not be endorsed.

Through March 31, 2004, certificates should be addressed to:

EquiServe

Dividend Reinvestment Dept.

P.O. Box 43010

Providence, RI 02940-3010

Through March 31, 2004, certificates sent by overnight delivery service should be addressed to:

EquiServe

Dividend Reinvestment Dept.

150 Royall Street

Canton, MA 02021

The stock certificates should not be endorsed.

19.    What happens to shares purchased under the plan?

Shares purchased under the plan will be automatically held in book entry form by the plan administrator in its name or the name of its nominee. The number of shares, including fractional interests, held for each participant will be shown on each investment statement. Participants may obtain a new certificate for all or some of the whole shares of stock held in their plan accounts by contacting the plan administrator. Any remaining shares will continue to be held in book entry form by the plan administrator.

Dividends on shares purchased through the plan, whether they are held by the participant in certificated form or in book entry form by the plan administrator, may be paid in cash to the shareholder by check or electronic deposit or reinvested pursuant to the shareholder’s instruction to the plan administrator contained in a completed enrollment application. Beginning April 1, 2004, a change to partial dividend reinvestment will require that shares be in certificated form on which dividends will be paid in cash rather than reinvested. These changes must be made by completion of a new enrollment application or by contacting the plan administrator online (not available through March 31, 2004) or by telephone at 1-800-543-3038.

Automatic Monthly Investments

20.    What is the automatic monthly investment feature of the plan and how does it work?

Participants may make optional cash investments of not less than $25 per investment nor more than a total of $100,000 during any calendar year by automatic bank deductions from a pre-designated U.S. bank account. If a participant has already established a plan account and wishes to initiate automatic monthly deductions, he or she must complete and sign an appropriate form provided by the plan administrator and return it to the plan administrator together with a voided blank check (for a checking account) or deposit slip (for a savings account) for the account from which funds are to be drawn. This process may also be completed online (not available through March 31, 2004). Forms will be processed and will become effective as promptly as practicable.