According to Sergio Corbucci, Marcello Mastroianni gave him the idea of a mute gunfighter when the actor told him that he had always wanted to do a Western, but unfortunately didn't speak English. When Corbucci first met Jean-Louis Trintignant, he learned that he didn't speak English either. Because he had a fascination with characters with a crippling weakness, Corbucci decided that this was the moment to turn the taciturn Spaghetti Western hero into a mute.
The snow in the town of Snow Hill was created by gallons of shaving cream.
Silenzio's distinctive rapid-firing pistol is the 7.63mm Mauser C96, nicknamed the "Broomhandle" for its distinctive wooden grip. The pistol was first produced in 1896, two years before the events of the film.
Loco's characterization is partially based on Gorca, the vampire played by Boris Karloff in Les trois visages de la peur (1963).
The film's Italian trailer includes an appraisal of the film attributed to 20th Century Fox (the film's distributor in Italy and other territories) co-founder Darryl F. Zanuck, which reads: ''Il migliore western all'italiana degli ultimi tempi'' (The best Spaghetti Western of recent times). In reality, Zanuck was offended by the film's grim ending, and refused to release it in the United States.