Roberto Rossellini and his future wife Ingrid Bergman met for the first time while making this movie.
A change in production company occurred when Ingrid Bergman replaced Anna Magnani as leading actress. The original company reacted by using the same plot for another movie, Vulcano, shot at the same time and in nearly the same places as Rossellini's movie.
Director Roberto Rossellini worked with no written screenplay but a handful of personal notes.
During production of this film, 'Ingrid Bergman' entered into an extra-marital affair with Roberto Rossellini and became pregnant. The resulting scandal in America effectively blacklisted her from the North American movie market and she was even condemned by politicians and religious figures. She was finally forgiven and welcomed back to America upon the success of Anastasia, but her Hollywood career was temporarily ended by this movie.
In the promotional material, Howard Hughes played up the parallels between the character she played and the recent indiscreet behavior of lead actress Ingrid Bergman. He re-cut the film behind Rosselini's back and refused to screen it for the press. The film got talked about before it was seen. It was banned outright in Memphis, and the Roman Catholic church urged its priests not to see it. It opened to phenomenal business, earning nearly $1 million in its first day.
Karin (Ingrid Bergman's character) says to Argentina's Consul that she was born on 8 May 1920. Director Roberto Rossellini was born on 8 May 1906.
U.S. Senator Edwin C. Johnson denounced the film, saying, "The degenerate Rosselini has deceived the American people with an idiotic story of a volcano and a pregnant woman. We must protect ourselves against such scourges."