As filed with the Securities and Exchange Commission on July 22, 2005
                                                      REGISTRATION NO. 333-74242
================================================================================

                       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 LIGHTING GROUP, INC. PROFIT SHARING RETIREMENT PLAN
                             FOR SALARIED EMPLOYEES
                      ZEP MANUFACTURING COMPANY 401(k) PLAN
                    SELIG CHEMICAL INDUSTRIES RETIREMENT PLAN
             ACUITY BRANDS, INC. 401(k) PLAN FOR CORPORATE EMPLOYEES
          ACUITY LIGHTING GROUP, INC. 401(k) PLAN FOR HOURLY EMPLOYEES
                          ENFORCER PRODUCTS 401(k) PLAN
  HOLOPHANE DIVISION OF ACUITY LIGHTING GROUP 401(k) PLAN FOR HOURLY EMPLOYEES
  HOLOPHANE DIVISION OF ACUITY LIGHTING GROUP 401(k) PLAN FOR HOURLY EMPLOYEES
                  COVERED BY A COLLECTIVE BARGAINING AGREEMENT

                              (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 to its Registration Statement on Form S-8, Registration No. 333-74242
(the "Registration Statement"), filed on November 30, 2001 with the Securities
and Exchange Commission, to deregister an aggregate of 423,768 shares of common
stock, par value $0.01 per share ("Common Stock"), along with the preferred
stock purchase rights, no par value ("Rights"), associated therewith, previously
registered on the Registration Statement and issuable under the Acuity Brands,
Inc. 401(k) Plan for Corporate Employees and the Acuity Lighting Group, Inc.
Profit Sharing Retirement Plan for Salaried Employees. This Post-Effective
Amendment No. 1 also deregisters the plan interests ("Plan Interests") in such
plans.

      The remaining shares of Common Stock, Rights associated therewith and Plan
Interests in the Employee Benefit Plans registered on the Registration Statement
in connection with the Zep Manufacturing Company 401(k) Plan, Selig Chemical
Industries Retirement Plan, Acuity Lighting Group, Inc. 401(k) Plan for Hourly
Employees, Enforcer Products 401(k) Plan, Holophane Division of Acuity Lighting
Group 401(k) Plan for Hourly Employees, and Holophane Division of Acuity
Lighting Group 401(k) Plan for Hourly Employees Covered by a Collective
Bargaining Agreement, as applicable, shall be unaffected by this Post-Effective
Amendment No. 1 to the Registration Statement.

                                        2



Item 8.         Exhibits.

Exhibit         Description
- -------         -----------

24.1 *          Powers of Attorney

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



                                   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 Pursuant to the requirements of the Securities Act of 1933, the trustees (or other persons who administer the employee benefit plan) have 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 the 22nd day of July, 2005. ACUITY LIGHTING GROUP, INC. PROFIT SHARING RETIREMENT PLAN FOR SALARIED EMPLOYEES ZEP MANUFACTURING COMPANY 401(K) PLAN SELIG CHEMICAL INDUSTRIES RETIREMENT PLAN ACUITY BRANDS, INC. 401(K) PLAN FOR CORPORATE EMPLOYEES ACUITY LIGHTING GROUP, INC. 401(K) PLAN FOR HOURLY EMPLOYEES ENFORCER PRODUCTS 401(K) PLAN HOLOPHANE DIVISION OF ACUITY LIGHTING GROUP 401(K) PLAN FOR HOURLY EMPLOYEES HOLOPHANE DIVISION OF ACUITY LIGHTING GROUP 401(K) PLAN FOR HOURLY EMPLOYEES COVERED BY A COLLECTIVE BARGAINING AGREEMENT By: Acuity Brands, Inc., Administrator of Plans By: /s/ Kenyon W. Murphy -------------------- Kenyon W. Murphy Senior Vice President and General Counsel

                                                                    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 333-74242) (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 333-74242) (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 333-74242) (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 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 333-74242) (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 333-74242) (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 333-74242) (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 333-74242) (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 333-74242) (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 333-74242) (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 333-74242) (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