The Medellín Cartel was a powerful and highly organized Colombian drug cartel and terrorist organization originating in the city of Medellín, Colombia, that was founded and led by Pablo Escobar. It is often considered to be the first major "drug cartel" and was referred to as such; due to the organization's upper echelons and overall power-structure being built on a partnership between multiple Colombian traffickers operating alongside Escobar. Included were Jorge Luis Ochoa Vásquez, Fabio Ochoa Vásquez, Juan David Ochoa Vásquez, José Gonzalo Rodríguez Gacha and Carlos Lehder. Escobar's main partner in the organization however was his cousin Gustavo Gaviria who handled much of the cartel's shipping arrangements and the more general and detailed logistical aspects of the cocaine trafficking routes and international smuggling networks which were supplying at least 80% of the world's cocaine during its peak. Gustavo, also known as León seems to have also had a strong hand in the cartel's unprecedented acts of narcoterrorism, right alongside his cousin Pablo and was considered to be second in command of the cartel and therefore one of Colombia's most wanted men, with both him and Escobar having arrest warrants pending from other nations where their criminal activity had spread to, such as in Spain and the U.S. Meanwhile, Pablo Escobar's brother Roberto Escobar acted as the organization's accountant. The cartel operated from 1976 to 1993 in Colombia (Antioquia), Bolivia, Panama, Central America, Peru, the Bahamas, the United States, as well as in Canada.

A drug cartel is a criminal organization composed of independent drug lords who collude with each other in order to improve their profits and dominate the illegal drug trade. Drug cartels form with the purpose of controlling the supply of the illegal drug trade and maintaining prices at a high level. The formations of drug cartels are common in Latin American countries. Rivalries between multiple drug cartels cause them to wage turf wars against each other.