The San Marino Communist Party (Partito Comunista Sammarinese) is a political party in San Marino. The PCS was formed in 1941.

Between 1945 and 1957 San Marino was ruled by a coalition of PCS and Partito Socialista Sammarinese.

In 1973 and in 1986 PCS entered into a coalition with Partito Democratico Cristiano Sammarinese.

In the 1980s PCS was estimated to have had around 1000 members.

The youth organizaton of PCS was Federazione Giovanile Comunista San Marino. FGCSM was a member of World Federation of Democratic Youth.

PCS published the newspaper La Scintilla.

In 1990 PCS renounced communism, and changed the party name to Partito Progressista Democratico Sammarinese. PPDS later evolved into the Partito dei Democratici.

In this process, a group of party members opposed to the transition to a non-communist party broke away and formed Rifondazione Comunista Sammarinese.