Ronald Colman
Role: Dr. Martin Arrowsmith
Helen Hayes
Role: Leora Tozer Arrowsmith
Richard Bennett
Role: Gustav Sondelius
A.E. Anson
Role: Professor Max Gottlieb
Clarence Brooks
Role: Dr. Oliver Marchand
Alec B. Francis
Role: Twyford
Claude King
Role: Dr. Tubbs
Bert Roach
Role: Bert Tozer
Myrna Loy
Role: Joyce Lanyon
Russell Hopton
Role: Terry Wickett
David Landau
Role: State Veterinarian
Lumsden Hare
Role: Sir Robert Fairland
Erville Alderson
Role: Pioneer (uncredited)
Ward Bond
Role: Cop (uncredited)
Beulah Bondi
Role: Mrs. Tozer (uncredited)
Florence Britton
Role: Miss Twyford (uncredited)
Nora Cecil
Role: Nurse (uncredited)
Sidney De Gray
Role: Dr. Hesselink (uncredited)
Cyril Delevanti
Role: Committee Member (uncredited)
Walter Downing
Role: City Clerk (uncredited)
Gibson Gowland
Role: Committee Member (uncredited)
Sherry Hall
Role: Reporter (uncredited)
Theresa Harris
Role: Native Mother (uncredited)
Raymond Hatton
Role: Drunk (uncredited)
Charlotte Henry
Role: Pioneer Girl (uncredited)
George Humbert
Role: Italian Uncle (uncredited)
DeWitt Jennings
Role: B.W. Tozer (uncredited)
Mike Lally
Role: Reporter (uncredited)
Lillian Lawrence
Role: West Indies Townswoman at Meeting (uncredited)
Carl M. Leviness
Role: Ship's Passenger (uncredited)
James A. Marcus
Role: Old Doctor (uncredited)
Eric Mayne
Role: Dignitary at Luncheon (uncredited)
Kendall McComas
Role: Little Johnny (uncredited)
Edmund Mortimer
Role: Ship's Passenger (uncredited)
John Qualen
Role: Henry Novak (uncredited)
Edward Reinach
Role: Dignitary (uncredited)
Milton Royce
Role: Intern (uncredited)
Harry Schultz
Role: Bartender (uncredited)
Pat Somerset
Role: Ship's Officer (uncredited)
Adele Watson
Role: Mrs. Novak (uncredited)
Bobby Watson
Role: Little Neighbor (uncredited)
Eric Wilton
Role: Ship's Officer (uncredited)