| David Duchovny | Fox Mulder |
| Gillian Anderson | Dana Scully |
| Doug Hutchison | Eugene Victor Tooms |
| Paul Ben-Victor | Dr. Aaron Monte
(as Paul Ben Victor) |
| Mitch Pileggi | Walter Skinner |
| Henry Beckman | Detective Frank Briggs |
| Timothy Webber | Detective Talbot |
| Jan D'Arcy | Judge Kann |
| Jerry Wasserman | Doctor Plith |
| Frank C. Turner | Doctor Collins |
| Gillian Carfra | Christine Ranford |
| Pat Bermel | Frank Ranford |
| Mikal Dughi | Dr. Pamela Karetzky |
| Glynis Davies | Defense Counsel Nelson |
| Steve Adams | Prosecution Counsel Myers |
| Catherine Lough Haggquist | Dr. Richmond
(as Catherine Lough) |
| William B. Davis | Smoking Man |
| André Daniels | Arlan Green
(as Andre Daniels) |