As novice detectives, Bud and Lou come face to face with the Invisible Man.
Bud Abbott
as Bud Alexander
Lou Costello
as Lou Francis
Nancy Guild
as Helen Gray
Arthur Franz
as Tommy Nelson
Adele Jergens
as Boots Marsden
Sheldon Leonard
as Boots Morgan
William Frawley
as Det. Roberts
Gavin Muir
as Dr. Philip Gray
Sam Balter
as Radio Announcer
John Daheim
as Rocky Hanlon
Walter F. Appler
as Professor Dugan (uncredited)
Bobby Barber
as Sneaky (uncredited)