Director Andrzej Wajda was himself a fighter in the Polish resistance movement against the Nazis in World War II and several scenes in the film were based on his experiences.
Teresa Izewska was paid the equivalent of $12 a month. Polish authorities bought her one dress and one pair of shoes to represent them at the Cannes Film Festival.
A lot of the film's crew members took part in the 1944 Warsaw uprising (e.g. cinematographer Jerzy Lipman or actor Tadeusz Janczar). Screenwriter Jerzy Stefan Stawinski used the sewers during the uprising in order to get from the southern district of Mokotów to the city center. As he said in an interview, each character in the film has at least one equivalent of a real-life insurgent he was acquainted with.
The sewer scenes were shot in the backyard of a film studio in Lódz. The actors had to wander there and forth in welded bathtubs full of water for several weeks. In order not to contract pneumonia, all of them had to drink vodka after getting out of the water.
The film is largely free of the usual overt Communist propaganda present in most films made by Communist Bloc nations. The toned-down film was made after the death of Soviet dictator Joseph Stalin, and after the fall of the Stalinist Polish regime of Boleslaw Bierut. This explains the more relaxed political censorship applied against this film.