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)

John Rawlins