David Duchovny
Dr. Ira Kane
Julianne Moore
Dr. Allison Reed, CDC
Orlando Jones
Prof. Harry Phineas Block
Seann William Scott
Wayne Grey
Ted Levine
General Russell Woodman
Ty Burrell
Colonel Flemming
Ethan Suplee
Deke
Michael Bower
Danny
Dan Aykroyd
Governor Lewis
Gregory Itzin
Cartwright
Pat Kilbane
Officer Johnson
Sarah Silverman
Denise
Michelle Wolff
Carla
Katharine Towne
Nadine
Stephanie Hodge
Jill Mason
John Cho
Student
Steven Gilborn
Judge Guilder
Wayne Duvall
Dr. Paulson
Kyle Gass
Officer Drake
Jerry Trainor
Tommy
Jennifer Savidge
Clare
Wendy Braun
Nurse Tate
Michael Chapman
Sheriff Long
Mary Pat Gleason
Customer
Andrew Bowen
Road Worker
Chris Wylde
Student
Tom Woodruff Jr.
Lead Primate Creature (uncredited)
Ashley Clark
Lt. Cryer