Exhibit 8.1



Subsidiaries of Ecopetrol S.A.

Ending Date: 31/03/2015



The following table  sets forth our subsidiaries,
their respective countries of incorporation, our percentage ownership in each (both directly and indirectly through
other subsidiaries) at March 31, 2015



|COMPANY                                                  |  | COUNTRY OF  INCORPORATION |  | OWNERSHIP |       
|-------------------------------------------------------- |  | ------------------------- |  | --------- | ------
|ANDEAN CHEMICALS LIMITED                                 |  | Bermuda                   |  |           | 100.00
|BLACK GOLD RE LIMITED                                    |  | Bermuda                   |  |           | 100.00
|CENIT TRANSPORTE Y LOGÍSTICA DE HIDROCARBUROS S.A.S.     |  | Colombia                  |  |           | 100.00
|ECOPETROL CAPITAL AG                                     |  | Switzerland               |  |           | 100.00
|ECOPETROL GLOBAL ENERGY S.L.U                            |  | Spain                     |  |           | 100.00
|ECOPETROL GLOBAL CAPITAL S.L.U.                          |  | Spain                     |  |           | 100.00
|EQUION ENERGÍA LIMITED.                                  |  | United Kingdom            |  |           | 51.00 
|HOCOL PETROLEUM LIMITED                                  |  | Bermuda                   |  |           | 100.00
|BIOENERGY S.A.**                                         |  | Colombia                  |  |           | 93.47 
|BIOENERGY ZONA FRANCA S.A.S**                            |  | Colombia                  |  |           | 93.47 
|COLOMBIA PIPELINES LIMITED**                             |  | United Kingdom            |  |           | 51.00 
|COMPOUNDING AND MASTERBATCHING INDUSTRY LTDA - COMAI  ** |  | Colombia                  |  |           | 100.00
|ECOPETROL AMERICA INC**                                  |  | United States             |  |           | 100.00
|ECOPETROL DEL PERU S.A.**                                |  | Peru                      |  |           | 100.00
|ECOPETROL OLEO & GAS DO BRASIL LTDA**                    |  | Brazil                    |  |           | 100.00
|ECOPETROL GERMANY GmbH**                                 |  | Germany                   |  |           | 100.00
|HOCOL S.A.**                                             |  | Cayman Islands            |  |           | 100.00
|OLEODUCTO BICENTENARIO DE COLOMBIA S.A.S.**              |  | Colombia                  |  |           | 55.97 
|OLEODUCTO CENTRAL S.A. - OCENSA**                        |  | Colombia                  |  |           | 72.65 
|OLEODUCTO DE COLOMBIA S.A. - ODC**                       |  | Colombia                  |  |           | 73.00 
|OLEODUCTO DE LOS LLANOS  ORIENTALES  S.A**               |  | Panama                    |  |           | 65.00 
|REFINERIA DE CARTAGENA S.A. *                            |  | Colombia                  |  |           | 100.00
|PROPILCO S.A.*                                           |  | Colombia                  |  |           | 100.00
|SANTIAGO OIL COMPANY**                                   |  | Cayman Islands            |  |           | 51.00 



*Direct and indirect participation.

**Solely indirect participation through other subsidiaries
or affiliates.