Richard Egan

as David Sheppard

Constance Dowling

as Joanna Merritt

Herbert Marshall

as Dr. Van Ness

John Wengraf

as Dr. Zeitman

Philip Van Zandt

as Dr. Pierre Elzevir

Valerie Vernon

as Mme. Elzevir

Byron Kane

as Dr. Carter

Stephen Roberts

as Maj. Howard

Michael Fox

as Dr. Hubertus

Aline Towne

as Dr. Kirby

Marian Richman

as Helen

Jean Dean

as Marna

William Schallert

as Engle

David Alpert

as Dr. Peter Burden

Tom Daly

as Senator