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, 2013.



|COMPANY                                                 | COUNTRY OF
        INCORPORATION | OWNERSHIP % | VOTING %
|------------------------------------------------------- | -------------------------------- | ----------- | --------
|                                                        |                                  |             |         
|Andean Chemicals Ltd.                                   | Bermuda                          | 100         | 100     
|Bioenergy S.A.**                                        | Colombia                         | 91.43       | 91.43   
|Bioenergy Zona Franca S.A.S.**                          | Colombia                         | 91.43       | 91.43   
|Black Gold Re                                           | Bermuda                          | 100         | 100     
|Cenit Transporte y Logística de Hidrocaburos S.A.S.     | Colombia                         | 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     
|                                                        |                                  |             |         
|EPI - Ecopetrol Pipelines International Limited         | Bermuda                          | 100         | 100     
|Equion Energia Limited**                                | United Kingdom                   | 51          | 51      
|Hocol Petroleum Limited**                               | Bermuda                          | 100         | 100     
|Hocol S.A.**                                            | Cayman Islands                   | 100         | 100     
|ODL Finance S.A.                                        | Panama                           | 65          | 65      
|Oleoducto Bicentenario de Colombia S.A.S.**             | Colombia                         | 55.97       | 55.97   
|Oleoducto Central S.A.**                                | Colombia                         | 72.65       | 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 Company.**                                 | Cayman Islands                   | 51          | 51      










*   Direct and indirect participation.

** Solely indirect participation through other subsidiaries
or affiliates.