This article analyzes the background and evolution of the affiliation of the Cuban left with the Comintern (Communist International), from their first contacts with the Bolshevik Revolution until the end of the 1920s. The authors recover a little-known history in historiography to show that, despite a series of disagreements between Moscow and Cuban communism, Comintern influence was by no means considered unfavorable to interests for Cuba’s communist movement. In fact, it helped to strengthen the left in that nation.