John Miljan
— Dr. Jones
Boyd Crawford
— Dr. Bates / William Wilson
Robert Middlemass
— Hartney Drew
Claire Du Brey
— Dr. Jones' Nurse Hazel
Clem Bevans
— Mr. Greene (uncredited)
Victor Kilian
— Jack Saunders (uncredited)
Ruth Robinson
— Mrs. Saunders (uncredited)
E. Alyn Warren
— Dr. Turner (as Fred Warren)
Barbara Bedford
— Miss Grant (uncredited)
Frederick Vogeding
— Dr. Jones' Viennese Associate (uncredited)
James Flavin
— Cop (uncredited)
Naomi Childers
— Patient (uncredited)