Ecopetrol (EC) 20-F 2010 FY Annual report (foreign)

Exhibit 8.1

Subsidiaries of Ecopetrol S.A.

The following table sets forth our subsidiaries, their respective countries of incorporation, our percentage ownership in each (both directly and indirectly through other subsidiaries) and our voting percentage in each at March 31, 2011.

COMPANY	COUNTRY OF INCORPORATION	OWNERSHIP %		VOTING %
Andean Chemicals Ltd.	Bermuda		100		100
Bioenergy S.A.**	Colombia		88.6		88.6
Bioenergy Zona Franca S.A.S.**	Colombia		88.6		88.6
Black Gold Re	Bermuda		100		100
Colombia Pipelines Limited**	United Kingdom		51		51
COMAI - Compounding and Masterbatching Industry Ltda.**	Colombia		100		100
Ecopetrol America Inc.*	United States		100		100
Ecopetrol Capital AG	Switzerland		100		100
Ecopetrol del Perú S.A.*	Perú		100		100
Ecopetrol Global Capital S.L.U.	Spain		100		100
Ecopetrol Global Energy S.L.U.	Spain		100		100
Ecopetrol Oleo e Gas do Brasil Ltda*	Brazil		100		100
Ecopetrol Pipelines International Ltd.**	Bermuda		100		100
Ecopetrol Transportation Company Limited	Cayman Islands		100		100
Ecopetrol Transportation Investments Ltd.*	Bermuda		100		100
Equion Energy Ltda	United Kingdom		51		51
Hocol Petroleum Limited**	Bermuda		100		100
Hocol S.A.**	Cayman Islands		100		100
Homcol Cayman Inc.**	Cayman Islands		100		100
ODL Finance S.A.	Panama		65		65
Offshore International Group Inc. – OIG(1)	United States		50		50
Oleoducto Bicentenario de Colombia S.A.S.*	Colombia		55.97		55.97
Oleoducto Central S.A.*	Colombia		72,6		72,6
Oleoducto de Colombia S.A.*	Colombia		73		73
Oleoducto de los Llanos Orientales S.A. **	Panama		65		65
Propilco S.A.*	Colombia		100		100
Refinería de Cartagena S.A.*	Colombia		100		100
Santiago Oil Co. **	Cayman Islands		51		51
Santiago Pipelines Co.**	Cayman Islands		51		51
Savia Perú S.A.**(1)	Peru		50		50

*   Direct and indirect participation.

** Solely indirect participation through other Subsidiaries or Affiliates.  OIG is the parent company of Savia Perú S.A., and Ecopetrol Transportation Company is the parent company of Ecopetrol Pipelines Ltd.

(1) Affiliate.