It was founded in 1917 as the Socialist Workers' Party (Partido Socialista Obrero, PSO) by Manabendra Nath Roy, a left-wing Indian revolutionary.

It is not clear whether the party was unable to recruit enough members or whether, fearing repression, it refused to turn membership rolls over to the Secretary of the Interior, then in charge of elections.

Over the next 30 years, the party had some minor influence in the Confederation of Mexican Workers (CTM) and among the intelligentsia of Mexico City.

[3] Following the electoral reform of 1977 that lowered the barrier for parties to get on the ballot, the PCM regained temporary registration for the 1979 mid-term elections.

Most members of the PSUM then merged with somewhat more moderate left-wing groups to form the Mexican Socialist Party (PMS) in 1987.