As filed with the Securities and Exchange Commission on July 22, 2005
                                                REGISTRATION NO. 333-74246
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                               -------------------

                         POST EFFECTIVE AMENDMENT NO. 1
                                       TO
                                    FORM S-8
                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                               -------------------

                               ACUITY BRANDS, INC.
             (Exact name of registrant as specified in its charter)

                  DELAWARE                                   58-2632672
       (State or other jurisdiction of                    (I.R.S. Employer
       incorporation or organization)                    Identification No.)

                               ACUITY BRANDS, INC.
                           1170 PEACHTREE STREET, N.E.
                                   SUITE 2400
                             ATLANTA, GEORGIA 30309
                                 (404) 853-1400
   (Address, including zip code, of registrant's principal executive offices)

                  ACUITY BRANDS, INC. LONG-TERM INCENTIVE PLAN

                              (Full title of plans)

                                KENYON W. MURPHY
                    SENIOR VICE PRESIDENT AND GENERAL COUNSEL
                               ACUITY BRANDS, INC.
                           1170 PEACHTREE STREET, N.E.
                                   SUITE 2400
                             ATLANTA, GEORGIA 30309
                                 (404) 853-1400

                (Name, address, including zip code, and telephone
               number, including area code, of agent for service)

- --------------------------------------------------------------------------------



                POST EFFECTIVE AMENDMENT NO. 1 - EXPLANATORY NOTE

      Acuity Brands, Inc. (the "Registrant") is filing this post-effective
amendment (this "Amendment") to the Acuity Brands, Inc. Registration Statement
No. 333-74246 (the "Registration Statement"), filed on November 30, 2001 with
the Securities and Exchange Commission to deregister 5,980,619 shares of common
stock, par value $0.01 per share ("Common Stock"), along with the preferred
stock purchase rights associated therewith ("Rights"), previously registered on
the Registration Statement.

      The Registrant has filed a new Registration Statement on Form S-8
(Registration No. 333-126521) for the Acuity Brands, Inc. Long Term Incentive
Plan (as amended and restated) (the "Amended LTIP"). The Registrant has carried
forward the 5,980,619 shares of Common Stock and associated Rights being
deregistered pursuant to this Amendment to the Registration Statement on Form
S-8 for the Amended LTIP.

      Furthermore, the $6,745 registration fee previously paid by the Registrant
to register the shares being deregistered under this Amendment has been carried
forward and applied to the registration fee due as a result of registering
8,980,619 shares on the new Registration Statement on Form S-8 for the Amended
LTIP.

      The remaining shares of Common Stock and associated Rights issuable
pursuant to the Acuity Brands, Inc. Employee Stock Purchase Plan and Acuity
Brands, Inc. 2001 Nonemployee Directors' Stock Option Plan registered on the
Registration Statement shall be unaffected by this Amendment.

                                       2



Item 8.        Exhibits.

Exhibit        Description

24.1 *         Powers of Attorney

- ------------------------
*     Filed herewith

                                       3



                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, Acuity Brands,
Inc. has duly caused this Post-Effective Amendment to the Registration Statement
to be signed on its behalf by the undersigned, thereunto duly authorized, in the
City of Atlanta, State of Georgia, on this 22nd day of July, 2005.

                                   ACUITY BRANDS, INC.

                                   By: /s/ Kenyon W. Murphy
                                       ----------------------------------------
                                       Kenyon W. Murphy
                                       Senior Vice President and General Counsel

      KNOW ALL MEN BY THESE PRESENTS, pursuant to the requirements of the
Securities Act of 1933, this Post-Effective Amendment to the Registration
Statement has been signed by the following persons in the capacities indicated
on July 22, 2005.

Signature                    Title

      *                      Chairman and Chief Executive Officer
- --------------------------
Vernon J. Nagel

      *                      Vice President and Controller; Interim Chief
- --------------------------   Financial Officer
Karen J. Holcom

      *                      Director
- --------------------------
Peter C. Browning

      *                      Director
- --------------------------
John L. Clendenin

     *                       Director
- --------------------------
Jay M. Davis

     *                       Director
- --------------------------
Earnest W. Deavenport, Jr.



      *                      Director
- --------------------------
Robert F. McCullough

      *                      Director
- --------------------------
Julia B. North

      *                      Director
- --------------------------
Ray M. Robinson

     *                       Director
- --------------------------
Neil Williams

* By: /s/ Kenyon W. Murphy
      -----------------------------
      Kenyon W. Murphy
      Attorney-in-Fact



                                                                    EXHIBIT 24.1

                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                                         /s/ Vernon J. Nagel
                                                     ---------------------------
                                                           Vernon J. Nagel

Dated:  July 22,  2005



                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                                         /s/ Karen J. Holcom
                                                     ---------------------------
                                                           Karen J. Holcom

Dated:  July 21,  2005



                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                                       /s/ Peter C. Browning
                                                     ---------------------------
                                                         Peter C. Browning

Dated:  July 22,  2005



                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                                        /s/ John L. Clendenin
                                                     ---------------------------
                                                          John L. Clendenin

Dated:  July 20,  2005




                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                                          /s/ Jay M. Davis
                                                     ---------------------------
                                                            Jay M. Davis

Dated:  July 21,  2005




                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                               /s/ Earnest W. Deavenport, Jr.
                                             ----------------------------------
                                                 Earnest W. Deavenport, Jr.

Dated:  July 21,  2005



                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                                      /s/ Robert F. McCullough
                                                     ---------------------------
                                                         Robert F. McCullough

Dated:  July 21,  2005




                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                                         /s/ Julia B. North
                                                     ---------------------------
                                                           Julia B. North

Dated:  July 20,  2005




                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                                         /s/ Ray M. Robinson
                                                     ---------------------------
                                                           Ray M. Robinson

Dated:  July 22,  2005




                                POWER OF ATTORNEY

      KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes
and appoints Vernon J. Nagel and Kenyon W. Murphy, and each of them
individually, his true and lawful attorneys-in-fact (with full power of
substitution and resubstitution) to act for him in his name, place, and stead in
his capacity as a director or officer of Acuity Brands, Inc., to file a Post
Effective Amendment to Acuity Brands, Inc.'s Registration Statement on Form S-8
filed with the Securities and Exchange Commission (File Number 333-74246) (the
"Registration Statement"), and any and all amendments thereto (including
post-effective amendments to the Registration Statement, and any subsequent
related registration statements and amendments thereto pursuant to Rule 462(b)
of the Securities Act of 1933, as amended), together with any exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact, and each of them individually,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in the premises, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact or either of them, or their substitutes, may
lawfully do or cause to be done by virtue hereof.

                                                          /s/ Neil Williams
                                                     ---------------------------
                                                            Neil Williams

Dated:  July 21,  2005