This film's title refers to both a series of mystery novels published in the 1940s by Simon & Schuster and a popular radio show adapted from the novels. The radio version ran from 1941 to 1952, and produced more than 500 episodes. The same material had been the source of a series of low-budget movies produced by Universal Pictures in the early 1940s.
This was the only film produced by M.R.S. Pictures, Inc., the initials of Richard B. Morros, Samuel Rheiner and Walter Shenson.
Inner Sanctum is a licensed adaptation of the Fritz Leiber Jr. science fiction/fantasy novella "Conjure Wife", although it bears no real resemblance to the novella which was also the inspiration for "Bewitched".
The failure of the original copyright holder to renew the film's copyright resulted in it falling into public domain, meaning that virtually anyone could duplicate and sell a VHS/DVD copy of the film. Therefore, many of the versions of this film available on the market are either severely (and usually badly) edited and/or of extremely poor quality, having been duped from second- or third-generation (or more) copies of the film.
A restored version of this film was presented at the 2022 UCLA Festival of Preservation accompanied by the short Buzzy Boop at the Concert (1938).