This paper analyzes through the Johansen cointegration methodology, the long-term relation between the stock price of Ecopetrol, listed on the Colombian Stock Exchange, and the WTI and Brent crude oil prices. The model results indicate that although the long-term relation between each of the reference oil brands and the stock price does not exist, there is evidence for a short-term relation between the Brent crude price and the price of Ecopetrol stock, as evidenced by the Granger causality test. This result can be useful for the policy maker and the shareholders.