Prospectus Supplement No. 3 (To Prospectus dated August 22, 2006)		Filed Pursuant to Rule 424(b)(3) and Rule 424(b)(7) Registration Number 333-136819

$143,750,000

QUANTA SERVICES, INC.

3.75% Convertible Subordinated Notes Due 2026
and the Common Stock Issuable Upon Conversion of the Notes

     This prospectus supplement relates to the resale by selling security holders of our 3.75% Convertible Subordinated Notes Due 2026 and the shares of our common stock issuable upon conversion of the notes.

     This prospectus supplement should be read in conjunction with, and may not be delivered or utilized without, the original prospectus dated August 22, 2006, Supplement No. 1 to such prospectus dated August 31, 2006 and Supplement No. 2 to such prospectus dated September 14, 2006. The terms of the notes are set forth in the original prospectus.

Investing in these securities involves risks. See “Risk Factors” beginning on page 10 of the prospectus.

     Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the notes or the shares of common stock issuable upon conversion of the notes or determined if the prospectus or this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is September 28, 2006.

SELLING SECURITY HOLDERS

     The information in the table appearing under the heading “Selling Security Holders” in the prospectus is amended by adding the information below with respect to persons not previously listed in the prospectus and by supplementing the information with respect to other persons previously listed in the prospectus that are listed below. This information was furnished to us by the selling security holders listed below on or before September 27, 2006.

     Based on information provided by the selling security holders, none of the selling security holders has held any position or office or has had any material relationship with us within the past three years.

Principal

Shares of

Shares of

Amount of

Common

Common

Notes

Stock

Shares of

Stock

Percentage

Beneficially

Percentage

Beneficially

Common

Beneficially

of Common

Owned and

of Notes

Owned Prior

Stock

Owned After

Stock

Name

Offered

Outstanding

to Offering

Offered

Offering

Outstanding

Credit Suisse Securities (USA) LLC(1)

$

4,604,000

3.20

%

205,444

205,444

—

—

DBAG London(2)

$

14,500,000

10.09

%

772,751

(3)

647,033

125,718

(3)

*

J.P. Morgan Securities Inc.(4)

$

2,489,000

1.73

%

111,067

111,067

—

—