 | Natasha Henstridge als Sil |
 | Ben Kingsley als Xavier Fitch |
 | Michael Madsen als Preston Lennox |
 | Marg Helgenberger als Dr. Laura Baker |
 | Alfred Molina als Dr. Stephen Arden |
 | Forest Whitaker als Dan Smithson, Empath |
 | Michelle Williams als Young Sil |
 | Jordan Lund als Aide |
 | Herta Ware als Mrs. Morris |
 | William Utay als Colleague |
 | Don Fischer als Aide |
| Scott McKenna als Train Hobo |
| Virginia Morris als Mother |
 | Jayne Luke als Snack Shop Clerk |
| David K. Schroeder als German Tourist |
 | David Jensen als Conductor |
 | Esther Scott als Female Conductor |
 | Shirley Prestia als Victoria Roth, Ph.D. |
 | David Selburg als Government Man |
 | Melissa Bickerton als Fitch's Secretary |
| Lucy Rodriguez als Wedding Dress Saleswoman |
| Scott Sproule als Team Driver |
 | Stogie Kenyatta als Cop |
 | Gary Bullock als Motel Clerk |
| Susan Hauser als Lab Worker |
 | William Bumiller als Club Bouncer |
 | Caroline Barclay als Drunken Girl |
 | Matthew Ashford als Guy in Club |
 | Anthony Guidera als Robbie, Guy Picking Up Sil |
| Sara Lise als Screaming Woman |
 | Whip Hubley als John Carey |
 | Patricia Belcher als Hospital Admittance Clerk |
 | Richard Fancy als Hospital Doctor |
| Leslie Ishii als Hospital Nurse |
 | Marliese Schneider als Abducted Woman |
| Robert Mendelson als Homeless Man |
| Pamela Cook als Commercial Model |
| Lisa Liberati als Bathroom Bimbo |
| Ed Stone als Waiter |
 | Dendrie Taylor als Marie |
| Kurtis Burow als Baby Boy |
 | Dana Hee als Creature Performer |
 | Frank Welker als Alien Sil (voice) |
| Justin Armao als Bystander (uncredited) |
| Jellybean Benítez als Club DJ (uncredited) |
 | Greg Bronson als Special Forces (uncredited) |
 | Jimmy Chunga als Commando (uncredited) |
| James Ent als Lt. Steele (uncredited) |
| Roman Güttinger als Doctor (uncredited) |
| Christopher Ivins als Soldier (uncredited) |
| Zak Knutson als Club Doorman (uncredited) |
 | Coati Mundi als Conga Player (uncredited) |
| Jason Newell als Special Forces (uncredited) |
| Dennis Feldman | Producer |
| Dennis Feldman | Author |
| Andrzej Bartkowiak | Director of Photography |
| Frank Mancuso Jr. | Producer |
| David Streit | Executive Producer |
| Conrad Buff IV | Editor |
| Roger Donaldson | Director |
| Christopher Young | Original Music Composer |
| Dan Webster | Art Direction |
| Margo Baxley | Costume Supervisor |
| Jackie Carr | Set Decoration |
| Joe I. Tompkins | Costume Design |
| Kenny Myers | Makeup Department Head |
| Cathy Sandrich Gelfond | Casting |
| John Muto | Production Design |
| Amanda Mackey | Casting |
| John Cade | Stunts |
| Pat Romano | Stunts |
| Mike Weathers | Lighting Technician |
| Dennis McNeill | Color Timer |
| John-Clay Scott | Stunts |
| Nina Paskowitz | Hair Department Head |
| Andy Gill | Stunts |
| Christopher Young | Orchestrator |
| David Streit | Unit Production Manager |
| Clarinda Wong | Assistant Editor |
| Pete Anthony | Orchestrator |
| Jeff Jarvis | Special Effects Coordinator |
| Charles Croughwell | Stunts |
| Jellybean Benítez | Music Supervisor |
| Patrick Phillips | Visual Effects |
| Nancy Young | Stunts |
| Mark Egerton | Associate Producer |
| Mark Jan Wlodarkiewicz | Sound Effects Editor |
| Elizabeth Lang | Casting Associate |
| Lanier Edwards | Stunts |
| Bob Edwards | Sound Re-Recording Mixer |
| John Tyrrell | Painter |
| Robert J. Visciglia Sr. | Property Master |
| Richard Davis, Jr. | Location Manager |
| Olivier Sarda | Digital Compositors |
| Randy Feemster | Additional Camera |
| Robert Bleckman | Set Dressing Artist |
| Jonathan Null | First Assistant Editor |
| Hugo Herrera | Greensman |
| Steve Adcock | First Assistant Camera |
| Jon Gardner | Craft Service |
| David Linck | Unit Publicist |
| Stan Harrison | Video Assist Operator |
| George A. Martin | Music Editor |
| Chris Snyder | Construction Coordinator |
| Lee A. Steadman | Location Scout |
| Mick Cukurs | Set Designer |
| John Philpotts | Additional Photography |
| Melinda Sue Gordon | Still Photographer |
| Alan Barnett | Digital Effects Supervisor |
| Theo Waddell | Visual Effects Editor |
| Dianna Stirpe | Dialogue Editor |
| Ruth Ann Crudup-Brown | Studio Teachers |
| Nicholas R. Allen | Boom Operator |
| Holly Schiffer | Choreographer |
| Lauren E. Polizzi | Assistant Art Director |
| Cary Griffith | Key Grip |
| Faye Brenner | Script Supervisor |
| Max Kleven | Stunt Coordinator |
| Joe Fordham | Production Coordinator |
| Tim Donelan | Leadman |
| Geri B. Oppenheim | Key Makeup Artist |
| Jeffrey D. Stevens | Set Medic |
| Doug Byers | Electrician |
| Jackie Caydam | Administration |
| Keith P. Cunningham | Art Department Coordinator |
| Tomas Mulrooney | Sculptor |
| Jay Boekelheide | Supervising Sound Editor |
| Francis N. 'Lucky' Costello | Standby Painter |
| Terry Bowen | Camera Operator |
| Lee Orloff | Sound Recordist |
| Moon Han | Systems Administrators & Support |
| Johnny Knight | Carpenter |
| Wayne Roberts | Transportation Captain |
| David Franklin Bergad | Assistant Sound Editor |
| Janine Cavoto | Set Dressing Supervisor |
| Ricardo F. Delgado | Storyboard |
| Cliff Fleming | Aerial Coordinator |
| Stephen St. John | Steadicam Operator |
| John Charles | Software Engineer |
| Paul J. Memmi | Translator |
| Ruth Caspary | Art Department Assistant |
| Eddie Lee Voelker | Transportation Coordinator |
| Richard Edlund | Visual Effects Supervisor |
| Gary Gagliardo | Construction Foreman |
| Jeff Homolya | Camera Department Manager |
| D.J. Plumb | Key Hair Stylist |
| John Bullard | Propmaker |
| Cheryl Gilbert | Stand In |
| Mark Egerton | First Assistant Director |
| Karin Joy | Visual Effects Coordinator |
| Robert Fernandez | Scoring Mixer |
| Gregory W. Smith | First Assistant Camera |
| Dylan Goss | First Assistant Camera |
| Dan Perri | Title Designer |
| Tracey Levy | Assistant Makeup Artist |
| Sean Phillips | Technical Advisor |
| Jim Pasque | Foley Recordist |
| Mark 'Boylee' Boyle | Camera Loader |
| Robert Leveen | Second Assistant Director |
| Guy Hietala | Set Painter |
| Gregg Guellow | Second Company Grip |
| Todd Griffith | Dolly Grip |
| Richard A. Kelley | Assistant Camera |
| Joel Negron | Assistant Editor |
| Pamela Alessandrelli | Assistant Production Coordinator |
| Ethan Van Hecke | Assistant Property Master |
| Sonia Apodaca | Location Coordinator |
| Thomas Milano | Supervising Music Editor |
| Evan Jacobs | Pyrotechnician |
| John Mann | Animation Director |
| Gary Burritt | Negative Cutter |
| Bobby Burton | Chief Lighting Technician |
| Ginger Reynolds | Executive Assistant |
| Mark Habegger | Production Assistant |
| Michael Chang | Matte Painter |
| Suzie Pelissier | Second Second Assistant Director |
| Rick Canelli | ADR Recordist |
| Katy Tatian-Genovese | Assistant Accountant |
| Lloyd Phillips | Production Consultant |
| Jennifer Myers | Foley Artist |
| Peter Davidian | Assistant Chief Lighting Technician |
| Adrienne Childers | Costumer |
| Ray Lykins | Stunt Double |
| Jim Eustermann | Project Manager |
| Grant Shaffer | Storyboard Artist |
| Thomas J. O'Connell | ADR Mixer |
| Richard Duarte | Foley Mixer |
| Curtis Collins | Assistant Location Manager |
| Christian Clarke | Key Set Production Assistant |
| Sara Feldman | Art Department Production Assistant |
| Xye | Visual Effects |
| Dan Wallin | Scoring Mixer |
| Tom Boyd | Musician |
| Debbie Evans | Stunts |
| Denise Lynne Roberts | Stunts |
| Gina Angela Ritchie | Stunts |
| Lisa McCullough | Stunts |
| Donna Evans | Stunts |
| Joni Avery | Stunts |
| H. R. Giger | Conceptual Design |
