John Barrymore

as Sherlock Holmes

Roland Young

as Dr. Watson

Carol Dempster

as Alice Faulkner

Gustav von Seyffertitz

as Professor Moriarty

Louis Wolheim

as Craigin

Percy Knight

as Sid Jones

William Powell

as Forman Wells

Hedda Hopper

as Madge Larrabee

Reginald Denny

as Prince Alexis

Peggy Bayfield

as Rose Faulkner

Lumsden Hare

as Dr. Leighton

Anders Randolf

as James Larrabee

Robert Schable

as Alf Bassick

David Torrence

as Count Von Stalburg

Albert Bruning

as Baron Orlonieff

Robert Fischer

as Otto

Jerry Devine

as Billy