| Name | Character | Episodes |
|---|---|---|
| Amy Price-Francis | Mel Porter | 22 |
| Adrian Paul | Cole / Daggon | 22 |
| Geraint Wyn Davies | Zin | 12 |
| Leanne Wilson | Jess Brown | 10 |
| Dean McDermott | Det. Vic Bruno | 6 |
| Richard Yearwood | Nestov | 3 |
| Katheryn Winnick | Laura | 2 |
| Scott McCord | Rudy / Yahir | 2 |
| Joanne Kelly | Zareth | 2 |
| Tara Spencer-Nairn | Erica / Vegna | 2 |
| Chyna | Rhee (as Joanie Laurer) | 2 |
| Mpho Koaho | Sirez / Jordan Baylor | 2 |
| Conrad Coates | Councilman Prestin | 2 |
| Markus Parilo | Haag | 2 |
| Peter Mensah | Marak | 1 |
| Patrick Garrow | Fletcher | 1 |
| Jake Simons | Young Man | 1 |
| Conrad Pla | Victor | 1 |
| Joseph Di Mambro | Sylvestri's Goon | 1 |
| Desmond Campbell | Reta | 1 |
| Deborah Odell | Dr. Colleen Hampton | 1 |
| Joe Pingue | Saahm | 1 |
| Amanda Brugel | Uniformed Officer | 1 |
| Julian Richings | Max | 1 |
| Thomas Mitchell | Vesser | 1 |
| Kim Roberts | Miss Price | 1 |
| Johnie Chase | Darrell | 1 |
| Ellen Dubin | Abby Swenson | 1 |
| Tony Nappo | Leon | 1 |
| Karen Robinson | Mrs. Baylor | 1 |
| Rachel Skarsten | Jamie Swenson / Lontoria | 1 |
| Fulvio Cecere | Marco Sylvestri | 1 |
| Peter Keleghan | Rahne Sullivann | 1 |
| Brenda Bazinet | Councilwoman Joan Elders | 1 |
| Sadie LeBlanc | Brooke | 1 |
| Tamara Hope | Tina | 1 |
| Lee Taylor-Allan | Admitting Nurse | 1 |
| Lyriq Bent | Bartender | 1 |
| Jordan Madley | Peggy's Friend | 1 |
| Gerry Mendicino | Nicholas Tavoulis | 1 |
| Richard Zeppieri | Bouncer | 1 |
| Richard Zeppieri | Jimmy | 1 |
| Derwin Jordan | Adderly | 1 |
| Dean Mckenzie | Torin | 1 |
| Rod Wilson | Tev / Gordon | 1 |
| Rod Wilson | Tev | 1 |
| James Gallanders | Rod Archer / Cole | 1 |
| Wayne Robson | Kaden | 1 |
| Christopher Redman | Rick | 1 |
| Rothaford Gray | Sheriff Dawnson / Dreakos | 1 |
| Jonathan Walker | Tech | 1 |
| Jonathan Walker | Tech #1 | 1 |
| Kristi Angus | Female Customer | 1 |
| Christine Tizzard | Mandy | 1 |
| Neil Crone | Chuck / Sedra | 1 |
| Tig Fong | Guard | 1 |
| Brandon Firla | Alien #2 | 1 |
| Jennifer Baxter | Marlene | 1 |
| Mike Realba | Lab Tech | 1 |
| Daniel Fathers | Tina's Dad | 1 |
| Christopher Lee Clements | Guard #3 | 1 |
| Don Francks | Wahota Keene | 1 |
| Alex Karzis | Logan Dunn | 1 |
| Ho Chow | Jezek | 1 |
| Michael Kremko | Doctor #1 | 1 |
| Kathryn Zenna | Trainer #1 | 1 |
| Tony Craig | Agent Micelli | 1 |
| Tony Craig | FBI Agent (uncredited) | 1 |
| Vito Rezza | Deputy Sheriff | 1 |
| Frank Chiesurin | Tony / Giusuppe / Cole | 1 |
| John Furey | Dr. Ross Connelly | 1 |
| John Furey | Dr. Russ Connelly | 1 |
| Patricia Gage | Judge Harriet Chapin | 1 |
| Nola Augustson | Roswell Waitress | 1 |
| Layton Morrison | Owen | 1 |
| Mung-Ling Tsui | TV Announcer | 1 |
| John MacDonald | Johnny | 1 |
| Paul Hopkins | Wes Furley / Kres | 1 |
| Paul Hopkins | Wes Furley / Ramel | 1 |
| Paul Hopkins | Wes Tarber / Ramel | 1 |
| Cindy Dolenc | Tiffany | 1 |
| Ron Kennell | Frederick J. Rappaport | 1 |
| Jennifer Vey | Nurse | 1 |
| Ryan Scott | Carver | 1 |
| Phillip MacKenzie | Baz | 1 |
| Larissa Gomes | Lina Tavoulis | 1 |
| Susanne Sutchy | Val | 1 |
| Myriam Sirois | Bridget | 1 |
| Joseph Pierre | Dude | 1 |
| Keith Kemps | Trof (as Keith Kamps) | 1 |
| Brian Paul | Captain | 1 |
| Thomas Hauff | Dr. Patterson | 1 |
| Janet Bailey | Agent Martha Kenny | 1 |
| Ted Ludzik | Thug #1 | 1 |
| Murray McRae | Animal Control Officer | 1 |
| Louis Di Bianco | Tommy Fusco | 1 |
| Sharon Brown | Young Woman | 1 |
| Natalie Brown | Peggy | 1 |