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