Ecopetrol

The company arose from the assets reverted from the "Mares Concession", awarded by President Rafael Reyes to the Tropical Oil Company, which began operating in 1921 with the Infantas 2 well and the subsequent start of production of the Cira-Infantas Field in the Middle Magdalena Valley (VMM). The giant oilfield is located 11 kilometres (6.8 mi) south of the city of Barrancabermeja and about 500 kilometres (310 mi) northeast of the capital, Bogotá. Even though there were attempts as early as 1941 for the Colombian government to legally take over the Tropical Oil Co., it was not until the expiration of the Concesión De Mares contract that a transfer of ownership took place.

The reversion of the "Mares Concession" ("Concesión De Mares") to the Colombian State on 25 August 1951 gave way to the Empresa Colombiana de Petróleos, which had been created in 1948 by means of Law 165 of that year. The growing company assumed the reverted assets of the Tropical Oil Co., which had begun oil activities in Colombia in 1921 with the implementation of the Cira-Infantas Field in the Middle Magdalena River Valley. Ecopetrol undertook activities throughout the oil chain as a state-owned industrial and commercial company in charge of administering the nation's hydrocarbon resources, and grew as other concessions reverted and became part of its operations.

The nationalization of Ecopetrol was not smooth and met with some opposition and skepticism as to whether the company would be able to keep up with the complex and expensive operations without outside expertise in the changing international market. A call for nationalization was nevertheless made.

In 1961, it assumed the direct management of the Barrancabermeja Refinery. Thirteen years later, it purchased the Cartagena Refinery, built by Intercol in 1956. In 1970, the company adopted its first by-laws, which ratified its nature as a state-owned commercial and industrial company, linked to the Ministry of Mines and Energy and fiscally supervised by the General Controllership of the Republic of Colombia. In September 1983, the discovery of the giant Caño Limón Field was announced. Ecopetrol, in association with Oxy, reported a reservoir with reserves estimated at 1.1 billion barrels (170,000,000 m3). Thanks to this field, the company began a new era and, in 1986, Colombia began to export oil again. During the 1990s, Colombia extended its oil self-sufficiency with the discovery of the giant Cusiana and Cupiagua Fields in the foothills of the Eastern Ranges of the Colombian Andes, bordering the Llanos Orientales. The fields were operated by BP.

In 2003, the Colombian government restructured the Empresa Colombiana de Petróleos in order to internationalize it and make the company more competitive within the global hydrocarbon industry. Decree 1760, dated 26 June 2003, modified the organic structure of the Empresa Colombiana de Petróleos and transformed it into Ecopetrol S.A., a public stock-holding corporation, wholly state-owned, associated with the Ministry of Mines and Energy, and governed by its by-laws contained in Notarized Document No. 2931, dated 7 July 2003, issued by the Second Notary Public of the Bogotá D.C. Circle. The transformation released the company from its role as administrator of the oil resources, and the ANH (Agencia Nacional de Hidrocarburos), or National Hydrocarbon Agency, was created to carry out that function.

As of 2003, Ecopetrol S.A. began a new phase in which, with greater autonomy, it accelerated its exploratory activities, strengthened its capacity to obtain results with a business and commercial vision, and sought to improve its competitiveness in the global oil market. Internationally, the company also operates in the Gulf of Mexico, from Houston, Texas; offshore in the Mexican Gulf of Mexico near Veracruz, Tabasco and Campeche; and offshore in Brazil, with offices based in Rio de Janeiro.

On 20 August 2021, the company acquired a 51.4% controlling stake in Interconexión Eléctrica, previously held by the Ministry of Finance and Public Credit, establishing a diversified energy conglomerate in South America.

Yuvelis Morales Blanco was awarded the Goldman Prize in 2026 for her advocacy against Ecopetrol's fracking.