Threshold

Donald Sutherland

Dr. Thomas Vrain

John Marley

Edgar Fine

Sharon Acker

Tilla Vrain

Mare Winningham

Carol Severance

Jeff Goldblum

Dr. Aldo Gehring

Michael Lerner

Henry De Vici

Richard Blackburn

Dr. Cutter

?

Michael C. Gwynne

Jay Wingate

Robert Joy

David Art

Allan F. Nicholls

Dr. Basil Rents

Kate Trotter

Mrs. Anderson

Lally Cadeau

Anita, Vrain's Secretary

Stuart Gillard

Dick Getts

Barbara Gordon

Wanda, Vrain's Scrub Nurse

?

Samantha Langevin

Mrs. Clure