Italy's largest trade-union federation. It was organized in Rome in 1944 as a nationwide labour federation to replace the dissolved Fascist syndicates. Its founders, who included communists, social democrats, and Christian Democrats, intended it to be the sole labour federation in Italy and to be generally independent of political parties. Within three years, however, Roman Catholics and Christian Democrats left the CGIL on the ground that it had become dominated by communists and formed the Free General Italian Confederation of Workers. In 1950 this organization merged with the Italian Federation of Labour, which had been formed by socialists and republicans who had left the CGIL, to form a major new labour federation, the Italian Confederation of Workers' Unions. In addition, the Italian Labour Union was founded in 1950 by socialists and republicans, thereby providing another noncommunist alternative to the CGIL.

These defections left the CGIL almost entirely dominated by communists, though it retained a significant socialist minority within its ranks. Despite its losses, the CGIL remained by far the largest and most powerful Italian labour federation throughout the postwar decades. It had almost 5,000,000 members and was strongly represented among heavy-industrial workers and agricultural labourers. The CGIL cultivated close ties with the Italian Communist Party and was affiliated with the World Federation of Trade Unions.