Revealing mistake: When the officials arrive at the Talbot family tomb to investigate the recent events, they find the crypt door unlocked. As they start to enter, the door opens on its own. When the camera cuts to an angle from inside the crypt, a thick cord can be seen pulling the door open.
Character mistake: When Inspector Owen calls the village police station the call is answered by a sergeant but at the end of the call Inspector Owen refers to him as Inspector. (00:10:00 - 00:11:00)
Continuity mistake: During Larry Talbot's first transformation into the Wolf Man in the hospital, he goes from wearing light-colored pajamas to a dark shirt and pants. When he awakens the next morning, he's back wearing the pajamas.
Other mistake: Despite the early scenes being set in Cardiff and its environs, not one character has a South Wales accent.