The main party on the revolutionary left in Portugal was the Portuguese Communist Party (Partido Comunista Português--PCP). The PCP had a long history of defiance to the Salazar dictatorship, and many of the party's leaders had spent long years in jail or in exile. Party members who remained in Portugal worked underground where they formed associations and organized the labor union Intersindical. The party was strongly Stalinist and Moscow-oriented.

Returning from exile in 1974, the PCP's leaders, many of whom were reputed to be capable and formidable politicians, tried to seize power by means of a coup, allying themselves with revolutionary elements in the Armed Forces Movement (Movimento das Forças Armadas--MFA). The party came close to seizing power in 1975 but failed because moderate elements within the armed forces and the political parties to the right of it were committed to Western democracy. Extensive financial aid from Western countries to these parties also contributed to the PCP's ultimate defeat.

The PCP, along with its far-left allies, got 17 percent of the vote in the first democratic election in Portugal in 1975, and for several elections after that it held its position at approximately 12 to 19 percent of the vote. But during the 1980s, as Portugal moved away from the radical politics of the mid-1970s and began to prosper economically, the PCP's popularity declined to less than 10 percent of the vote. The party remained strong in the trade unions, but younger members of the party challenged the old leadership and questioned the party's hard-line Stalinist positions. Some of these young challengers were expelled from the party. The collapse of the communism in Europe, the aging of the party's leadership (the party had been headed by Álvaro Cunhal since 1941) and of its membership, and the party's poor showing in elections indicated that the party would either have to transform itself fundamentally or fade away as a political force.

Data as of January 1993