After filming was completed, Lou Costello was bedridden for several months due to a relapse of rheumatic fever, which he originally battled in 1943. As a result, the duo did not make another film together until Abbott and Costello in the Foreign Legion, a year later.
The film was originally banned in Denmark due to the scene where corpses play cards.
The original script 'Easy Does It', was originally intended as a vehicle for Bob Hope. After the huge success of Bud Abbott Lou Costello Meet Frankenstein, Universal-International wanted another "horror" comedy with Bud Abbott and Lou Costello, so the script was rewritten for them. Oddly enough, the role played by Boris Karloff was originally written for a woman.
The role eventually played by Boris Karloff was originally a female character named Madame Switzer in the final shooting script which was then titled, 'Abbott and Costello Meet the Killers'. Five days before shooting, Karloff was hired and the character was changed to a swami.