| David Duchovny | Fox Mulder |
| Gillian Anderson | Dana Scully |
| Charles Cioffi | Section Chief Scott Blevins |
| Cliff De Young | Dr. Jay Nemman
(as Cliff DeYoung) |
| Sarah Koskoff | Theresa Nemman |
| Leon Russom | Detective Miles |
| Zachary Ansley | Billy Miles |
| Stephen E. Miller | Coroner Truitt |
| Malcolm Stewart | Dr. Glass |
| Alexandra Berlin | Orderly |
| Jim Jansen | Dr. Heitz Werber |
| Ken Camroux-Taylor | Third Man
(as Ken Camroux) |
| Doug Abrahams | Patrolman #1
(as Doug Abrams) |
| William B. Davis | Smoking Man |
| Katya Gardner | Peggy O'Dell
(as Katya Gardener) |
| Ric Reid | Asst. Coroner |
| Lesley Ewen | Receptionist |
| J.B. Bivens | Truck Driver |
| Laura Lee Connery | Karen Swenson
(uncredited) |
| Joe Doserro | Officer #1
(uncredited) |
| Amram Ducovny | Passanger in the Plane
(uncredited) |
| Christopher Hutson | Mr. Burrad
(uncredited) |
| Tim Ransom | Ethan Minette
(uncredited) |
| June B. Wilde | Nurse Cooley
(uncredited) |