Melodia Fatal

Basil Rathbone

Sherlock Holmes

Nigel Bruce

Dr. John H. Watson

Patricia Morison

Mrs. Hilda Courtney

Frederick Worlock

Colonel Cavanaugh

Harry Cording

Hamid

Carl Harbord

Inspector Hopkins

Holmes Herbert

Ebenezer Crabtree

Edmund Breon

Julian 'Stinky' Emery

Patricia Cameron

Evelyn Clifford

Mary Gordon

Mrs. Hudson

Ian Wolfe

Commissioner of Scotland Yard

Leyland Hodgson

Tour Guide

Marjorie Bennett

Antique Shop Assistant (uncredited)

William H. O'Brien

Detective at Murder Scene

Frank Baker

Photographer

Sally Shepherd