FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * DREYER ALEC G   2. Issuer Name and Ticker or Trading Symbol DYNEGY INC /IL/ [DYN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Executive Vice President-GEN. (Last) (First) (Middle) 1000 LOUISIANA STREET, SUITE 5800 3. Date of Earliest Transaction (Month/Day/Year) 08/17/2005 (Street) HOUSTON, TX 77002 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Stock 08/17/2005   M   30,000 A $ 1.77 137,277 (1) D   Class A Common Stock               11,050 I By 401(k) Plan (2) Class A Common Stock               4,542 I By 401(k) Plan (3)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Employee Stock Option (right to buy)

$ 1.77

08/17/2005

M

30,000

(4)

02/04/2013

Class A Common Stock

30,000

$ 0

30,000

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
DREYER ALEC G 1000 LOUISIANA STREET SUITE 5800 HOUSTON, TX 77002			Executive Vice President-GEN.

Signatures

/s/ Carolyn M. Campbell, Attorney-in-Fact		08/19/2005
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Includes 37,109 shares of restricted Class A Common Stock which vest on February 10, 2007 and 27,267 shares of restricted Class A Common Stock which vest on January 19, 2008.
(2)	Rounded. Reflects shares held for the Reporting Person's account by the Trustee of the Dynegy Inc. 401(k) Savings Plan as of August 17, 2005.
(3)	Rounded. Reflects shares held for the Reporting Person's account by the Trustee of the Dynegy Midwest Generation Inc. 401(k) Savings Plan as of August 17, 2005.
(4)	Options granted February 4, 2003 covering 90,000 shares become exercisable in three equal annual installments beginning February 4, 2004.

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