After the beginning of the Military Regime in Brazil with a coup in 1964, some leftist organizations opted ideologically and strategically for the armed struggle. The Cuban experience, where Fidel Castro’s guerrilla forces had overthrown the Batista dictatorship and taken political power, was a clear inspiration. The pronouncement of “Ato Institucional n. 5” on 13 December 1968, an extremely hard move from the regime, was the trigger for several groups to move forward. However, lacking support from the society at large, by the end of 1971 all urban guerrilla groups had been destroyed or disbanded. The most important guerrilla leaders were dead. A remaining experience of rural guerrilla in the Araguaia region was finally exterminated in 1975. Who were the people that took part in the armed struggle against the dictatorship in Brazil? What were their political-ideological orientations and the main actions they took? The chapter addresses these issues and also mentions how the repression from the regime acted to destroy the guerrilla and how, half a century later, this combat is represented in memorialist and historiographic disputes.