The Communist Party of Belgium was formed at a congress in Anderlecht, Brussels on 3–4 September 1921. KPB/PCB was formed through the unification of two groups, the Communist Party led by War Van Overstraeten and the Belgian Communist Party led by Joseph Jacquemotte, following a split from the Belgian Workers Party. At the time of its foundation, KPB/PCB had around 500 members.[1] KPB/PCB became the Belgian section of the Communist International. The party gained parliamentary presence in 1925, as both Van Overstraeten and Jacquemotte were elected to the Chamber of Representatives. By 1935 KPB/PCB had 9 deputies in the Chamber and 4 members in the Senate. In 1938 it had a membership of about 8,500.
During the Second World War, the party had to go underground during German occupation. The party was also closely affiliated with the Partisans Armés, a resistance group during the occupation, however in 1943 much of the party leadership was arrested by German forces. After the end of the war, the party was strengthened and obtained 25% in the parliamentary elections. The party participated in a coalition government with the socialists and the liberals from 1946 to 1947.
On 18 August 1950 the party chairman, Julien Lahaut, was assassinated.
In the mid 1960s the U.S. State Department estimated the party membership to be approximately 9,890.[2]
KPB/PCB lost its parliamentary presence in 1985.[3]
Marcel Levaux (1926–2006), last mayor of Cheratte (Liège province) from April 1971 to December 1976 (in 1977 this commune was absorbed into Visé), deputy from 1968 to 1981
René Noël, last mayor of Cuesmes (Hainaut province) from 1965 to 1971 (in 1972 this commune was absorbed into Mons), senator from 1949 to 1950, then again from 1954 to 1974
a In the 1971 and 1977 General Elections, the Communist Party used separate lists for both Flanders and Wallonia, despite remaining a single party b It is unclear whether the Communist Party decided not to run separate lists for the 1974 General Election or the data for regional lists is simply not available[citation needed]
^Gotovitch, José (9 August 2010). "Jacquemotte, Joseph". Le Maitron: Dictionnaire biographique, mouvement ouvrier, mouvement social (in French). Maitron/Editions de l'Atelier. Retrieved 26 June 2023.
Gotovitch, José (1992). Du rouge au tricolore: les communistes belges de 1939 à 1944; un aspect de l'histoire de la résistance en Belgique. Brussels: Editions Labor. ISBN978-2804006426.
