The Comintern had, at the first Congress, voting delegates from the following groups:

• Communist Party of Armenia
• Central Bureau's Azerbaijani Section
• Communist Party of Bulgaria
• Socialist Workers' Party of China
• Communist Party of Czechoslovakia
• Communist Party of German Austria
• Communist Party of Finland
• Communist Party of France
• Zimmerwald Left Wing of France
• Central Bureau's Georgian Section
• Communist Party of Germany
• Communist Party of Great Britain
• Communist Party of Hungary
• Worker's Union of Korea
• Communist Party of Latvia
• Social-Democrats of the Netherlands
• Central Bureau's Persian Section
• Communist Workers Party of Poland
• Balkan Revolutionary People's of Russia
• Communist Party of the Soviet Union
• Social Democratic Left Party of Sweden
• Communist Party of Switzerland
• Central Bureau's Turkestan Section
• Communist Party of Ukraine
• Socialist Labor Party of the United States
• Socialist Propaganda League of the United States
• Communist Party of Volga region in Germany
• Communist Party of Yugoslavia

See also: List of Communist Parties