• 
  Don Taylor

  regizor

• 
  Paul Dehn

  scenarist

• 
  Roddy McDowall

  Cornelius
• 
  Bradford Dillman

  Dr. Lewis Dixon
• 
  Natalie Trundy

  Dr. Stephanie 'Stevie' Branton
• 
  Eric Braeden

  Dr. Otto Hasslein
• 
  William Windom

  Presedintele
• 
  Sal Mineo

  Dr. Milo

• 
  Roy Glenn

  Avocat
• 
  James W. Gavin

  Helicopter Pilot
• 
  Jason Evers

  E-2
• 
  M. Emmet Walsh

  Aide
• 
  Donald Elson

  Curator
• 
  Ricardo Montalban

  Armando
• 
  Joe Gray (I)

  Bodyguard

• 
  Walker Edmiston

  Talking Baby Chimp
• 
  Robert Nichols

  Reporter
• 
  James Sikking

  Control Room Officer
• 
  Norman Burton

  Army Officer
• 
  Kim Hunter

  Zira
• 
  Albert Salmi

  E-1
• 
  Peter Forster

  Cardinal
• 
  Harry Lauter

  General Winthrop
• 
  John Randolph

  Chairman