It was formed in 1986 by Alberto Fernández Malo, who broke away from the Spanish Socialist Workers' Party (PSOE).[1] Fernández had previous been a member of the Socialist Left, a leftist tendency inside PSOE.[2] The party took part in founding the United Left (IU) in 1986.
In the 1993 parliamentary election Octubre Socialista got 540 votes (0.14% of the votes in the province).[3] In the municipality of Torreperogil it obtained 211 votes (4.07%). In the city of Jaén, it obtained 125 votes (0.2%).