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WRITER’S DIRECT NUMBER:

(212) 848-5009

WRITER’S EMAIL ADDRESS:

astolper@shearman.com

December 23, 2010

BY EDGAR AND FACSIMILE

Ms. Sandy Eisen

United States Securities and Exchange Commission

Division of Corporation Finance

450 Fifth Street, N.W.

Washington, D.C. 20549-0405

Tel: (202) 551-3864

Ecopetrol S.A.

Form 20-F for Fiscal Year Ended December 31, 2009

Filed July 15, 2010

File No. 001-34175

Dear Ms. Eisen:

Ecopetrol S.A. (the “Company”) has received a comment letter dated December 17, 2010 from the staff of the Division of Corporate Finance (the “Staff”) of the United States Securities and Exchange Commission concerning the Company’s (i) annual report on Form 20-F for fiscal year ended December 31, 2009 and (ii) response letter dated September 28, 2010 to a comment letter dated August 30, 2010 from the Staff. Pursuant to our phone conversation on December 22, 2010, we hereby advise the Staff that the Company will submit a response to the Staff’s letter no later than January 19, 2011.

If you have any questions or wish to discuss any matters relating to the foregoing, please contact me at 212-848-5009 or Adriana M. Echeverri, Chief Financial Officer of the Company, at 011-57-1234-4254.

	Very truly yours,



	/s/ Antonia E. Stolper

cc:	Javier G. Gutiérrez - Chief Executive Officer – Ecopetrol S.A.

Adriana M. Echeverri – Chief Financial Officer – Ecopetrol S.A.

Alejandro Giraldo – Investor Relations – Ecopetrol S.A.

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