Polish Defense Minister Radoslaw Sikorski said some of the documents indicated that the Soviet-led military alliance was prepared to use nuclear weapons in Europe as part of a war with NATO.
Sikorski said he was giving the National Remembrance Institute more than 700 files that had been kept secret until now.
He said they were valuable for educating people about how Poland was "kept as an unwilling ally of the Soviet Union during the Cold War."
Among those documents, Sikorski said, was a detailed plan for pushing Warsaw Pact forces to the Atlantic in a war with NATO.
He said other documents offered new insight into the 1968 Warsaw Pact invasion of Czechoslovakia.