This movie was originally intended to be a sequel to Goldginger (aka The Amazing Doctor G (1965)), Italian comedians Franco Franchi and Ciccio Ingrassia's Goldfinger (1964) spoof. When American International Pictures came on board as a co-financier, it was decided to shoot one movie but make two identifiably different films; one each for the Italian and English speaking markets. The Italian film was to be a vehicle for the two Italian comedians and the English version a Dr. Goldfoot sequel, thus achieving two commercial goals of two different national investors. As such, this film was edited into two completely different movies.
Dr. Goldfoot and the Bikini Machine (1965) was only a moderate box-office success in America but a big hit in Italy. As such, this sequel was shot in Italy with Italian director Mario Bava and with two Italian comedic movie stars, Franco Franchi and Ciccio Ingrassia.
Apparently director Mario Bava tried to withdraw from directing this film, but was contractually obligated to see it through.
This movie's Italian version's title "Le spie vengono dal semifreddo" is a parody of The Spy Who Came in from the Cold (1965). This title translates literally into English as "The Spies Who Came In from the Semi-Cold", or more commonly, "The Spies Who Came In From the Frozen Custard."
The English language version of this film was re-written, re-edited, and re-scored without the involvement of director Mario Bava whose post-production imprint was only left on the Italian language version of this film.