Originally the film credits were to read "Errol Flynn in The Sisters," but Bette Davis demanded equal billing alongside Errol Flynn. She also pointed out that the original credits had an unwelcome sexual connotation.
According to contemporary news reports, Anita Louise hated wearing a corset for this film. Bette Davis didn't mind it quite so much.
The earthquake sequence took three weeks to shoot and and the special sets that were constructed cost $200,000 ($4.3M in 2023).
In the novel on which the film was based, the character of Louise Elliott ends up marrying a different man in the denouement.