Leader del Partito:
Amadeo Bordiga (gennaio 1921 - marzo 1923)
Palmiro Togliatti & Angelo Tasca (giugno 1923 - August 1924)
Antonio Gramsci (August 1924 - January 1926)
Secretaries-General:
Antonio Gramsci (January-November 1926)
Camilla Ravera (1927-1930)
Palmiro Togliatti (1930-1934 )
Ruggero Grieco (1934 - 1938)
Palmiro Togliatti (1938 - August 1964)
Luigi Longo (August 1964 - March 1972)
Enrico Berlinguer (March 1972 - June 1984)
Alessandro Natta (June 1984 - June 1988)
Achille Occhetto (June 1988 - February 1991)
