Boris Karloff
Gruesome

Ralph Byrd
Dick Tracy

Anne Gwynne
Tess Trueheart

Edward Ashley
Dr. L.E. Thal

June Clayworth
Dr. I.M. "Irma" Learned

Lyle Latell
Pat Patton

Tony Barrett
Melody

Skelton Knaggs
X-Ray

James Nolan
Dan Sterne

Joseph Crehan
Chief Brandon

Milton Parsons
Dr. A. Tomic

Ernie Adams
Waiter at Hangman's Knot (uncredited)

Phil Arnold
Sneezing Bank Customer (uncredited)

Walter Bacon
Bar Patron (uncredited)

Lex Barker
City Hospital Driver (uncredited)

Eddie Borden
Bank Customer (uncredited)

Robert Bray
Sergeant (uncredited)

Robert Clarke
Fred (Police Analyst) (uncredited)

George Cooper
Stone (Bank Teller) (uncredited)

Suzi Crandall
Blonde Bank Customer (uncredited)