Jack Nicholson as Randle Patrick "R.P." McMurphy
Louise Fletcher as Nurse Mildred Ratched
Will Sampson as "Chief" Bromden
William Redfield as Dale Harding
Brad Dourif as Billy Bibbit
Sydney Lassick as Charlie Cheswick
Christopher Lloyd as Max Taber
Danny DeVito as Martini
Dean Brooks as Dr. John Spivey
William Duell as Jim Sefelt
Vincent Schiavelli as Bruce Frederickson
Michael Berryman as Ellis
Alonzo Brown as Attendant Miller
Mwako Cumbaka as Attendant Warren
Nathan George as Attendant Washington
Marya Small as Candy
Scatman Crothers as Night Guard Turkle
Phil Roth as Woolsey
Louisa Moritz as Rose
Peter Brocco as Col. Matterson
Delos V. Smith Jr. as Scanlon
Josip Elic as Bancini
Mimi Sarkisian as Nurse Pilbow
Ted Markland as Hap Arlich
Mary Costa as Mrs. Johnson