Lionel Barrymore
— Dr. Leonard Gillespie
Lew Ayres
— Dr. James Kildare
Lynne Carver
— Alice Raymond
Nat Pendleton
— Joe Wayman
Jo Ann Sayers
— Barbara Chanler
Samuel S. Hinds
— Dr. Stephen Kildare
Emma Dunn
— Mrs. Martha Kildare
Walter Kingsford
— Dr. P. Walter Carew
Truman Bradley
— Jack Hamilton
Monty Woolley
— Dr. Lane-Porteus
Pierre Watkin
— Mr. Robert Chanler
Nella Walker
— Mrs. Chanler
Murray Alper
— Blue Swan Waiter (uncredited)
Don 'Red' Barry
— Dr. Collins (uncredited)
Granville Bates
— Harry Cook (uncredited)
Barbara Bedford
— Nurse (uncredited)
Margaret Bert
— Little Boy's Mother (uncredited)
Marie Blake
— Miss Sally Green (uncredited)
Virginia Brissac
— Boardinghouse Landlady (uncredited)
John Butler
— Coronary Patient (uncredited)
Don Castle
— Dr. Bates (uncredited)
Janice Chambers
— Maggie (uncredited)
Roger Converse
— Dr. Joiner (uncredited)
Nell Craig
— Nurse Parker (uncredited)
Frank Dae
— President, Board of Directors (uncredited)
Bess Flowers
— Nurse (uncredited)
Brenda Fowler
— Head Nurse (uncredited)
Harrison Greene
— Bartender (uncredited)
Howard Hickman
— Dr. Harris (uncredited)
Cy Kendall
— Charlie (uncredited)