This article examines the Soviet intervention in the Spanish Civil War through the personal diaries of the Consul General of the USSR in Barcelona. Vladimir Antonov-Ovseenko completed five diaries sent to the People's Commissariat for Foreign Affairs of the USSR during the month of October 1936. In these diaries, he recounted his personal impressions as well as his activity of his initial stay in the Catalonian capital, which offer an intimate view and detailed picture of the Soviet intervention in Spain. Winning the war was the central objective of Soviet Consulate in Spain, in accordance with the principles of Soviet Collective Security Policy. This central objective, focused on trade relations, military operations and particular relationship with the anarchists and the regional Government of Catalonia and the Government of the Republic, did not show the slightest hint of wanting to sovietize the Spanish Republic. For this reason, the historiographical debate about the logic of Soviet intervention in Spain has a new proof against the thesis of a preconceived plan to impose the soviet political, social and economic model on Spain in 1936.