* FakeNationality: Swedish Warner Oland playing Asian Dr. Yogami.
* WhatCouldHaveBeen:
** The original werewolf design by Jack Pierce was reportedly similar to the one in ''Film/TheWolfMan1941'', but Glendon's actor Henry Hull refused to wear it citing the fact that the script stated that the werewolf should have been recognized as Glendon even in werewolf form and the Wolf Man-like appearance of Pierce's make-up would not have made Hull recognizable.
** Creator/BelaLugosi was considered for the role of Dr. Yogami.
** Universal originally planned to do a film version of Guy Endore's book ''The Werewolf of Paris'', but the plans fell through when Endore was hired by Creator/MetroGoldwynMayer as a script writer.
** The role of Glendon was originally meant for Creator/BorisKarloff.