To prepare for this role, Sylvester Stallone did eight months of training for four hours a day. He also took SWAT combat, archery and survival courses.
The film is dedicated to special effects technician Cliff Wenger Jr., who was accidentally killed by one of the film's explosions.
Dolph Lundgren was initially signed as the Russian Lieutenant Colonel Podovsky (played by Steven Berkoff), when Sylvester Stallone realized that it was the same man who was going to be in Rocky IV (1985), so they paid off the contract.
At the time of filming (1985), there were close to 2,500 Vietnam veterans still missing in action.
When this film was released in the Soviet Union, dialogue was changed so that the year is 1943; the Soviets are Nazis, the Vietnamese are Japanese, and the POWs are World War II prisoners ostensibly still being held somewhere in the Philippines.