| Members (1955) | |
|---|---|
| Albania | People's Republic of Albania | 
| Bulgaria | People's Republic of Bulgaria | 
| Czechoslovakia | Czechoslovak Republic | 
| East Germany | German Democratic Republic | 
| Hungary | Hungarian People's Republic | 
| Poland | Polish People's Republic | 
| Rumania | Rumanian People's Republic | 
| Soviet Union | Union of Soviet Socialist Republics |