Whit Bissell as Prof. Frankenstein

Phyllis Coates as Margaret

Robert Burton as Dr. Karlton

Gary Conway as Bob / Teenage Monster

George Lynn as Sgt. Burns

John Cliff as Sgt. McAffee

Marshall Bradford as Dr. Randolph

Claudia Bryar as Arlene's Mother

Angela Austin as First Victim

Russ Whiteman as Dr. Elwood

Charles Seel as Mr. Sexton, the jeweler

Paul Keast as Man at Crash

Gretchen Thomas as Woman in Corridor

Patrick Miller as Police Officer (as Pat Miller)

Joy Stoner as Arlene

Larry Carr as Young Man (uncredited)

George DeNormand as Party Guest (uncredited)

James Gonzalez as Party Guest (uncredited)

Frank McLure as Party Guest (uncredited)

William H. O'Brien as Rooming House Boarder (uncredited)

Norman Stevans as Party Guest (uncredited)

Arthur Tovey as Party Guest (uncredited)