[citation needed] The origins of the party can be traced directly to the first visit Commander Fidel Castro made to Venezuela, specifically to its capital Caracas in January 1959, to celebrate the first anniversary of the fall of the military dictatorship of General Marcos Pérez Jiménez.

At the exact moment of the creation of MIR, it pleaded, according to their weekly Izquierda, as a "Marxist party, their goal was to drive the Venezuelan people to the path of socialism through the National Revolution realizing a clearly anti-imperialist and anti-feudal program".

Some of their leaders included Domingo Alberto Rangel, Jose Manuel "Chema" Saher, Américo Silva, Americo Martin, Simon Saez Mérida, Etanislao Gonzalez, Jose Manuel Gilli Trejo, Ruben Jaramillo, Gabriel Puerta Aponte, Victor and Fernando Soto Rojas, Julio Escalona, Marcos Gomez, Carlos José Ugueto Marino and Carlos Betancourt.

One of the most active cells was named "Van Troi" led by Jesus Alberto Marquez Finol who executed many officers, soldiers and civilians for not supporting the armed struggle, such as the shooting of Doctor Alfredo Seijas, Legal Counsel of the DIGEPOL in September 1965, who was a lawyer and was abducted from inside the Central University of Venezuela (UCV) and moved towards urbanization Macaracuay of Caracas, to run to death.

And the third group led by Jorge Rodriguez and Julio Escalona who decide to start an urban guerrilla struggle but combined with legal means, creating the Revolutionary Organization (OR), whose legal facade would be called Socialist League and would participate in the elections being led by Carmelo Laborit, Jorge Rodriguez, Orlando Yajure, Oscar Battaglini, Norelkis Meza and David Nieves.