Jessica Alba .... Max Guevera/X5-452/X5-453
Michael Weatherly .... Logan Cale/Eyes Only
Alimi Ballard .... Herbal Thought (2000-2001)
Jennifer Blanc .... Kendra Maibaum (2000-2001)
Richard Gunn .... Calvin Simon 'Sketchy' Theodore
J.C. MacKenzie .... Reagan 'Normal' Ronald
Valarie Rae Miller .... Cynthia 'Original Cindy' McEachin
John Savage .... Colonel Donald Michael Lydecker (2000-2001)
Jensen Ackles .... Ben/x5-493 (2000) Alec/X5-494 (2001-2002)
Martin Cummins .... Ames White (2001-2002)
Kevin Durand .... Joshua (2001-2002)
Ashley Scott .... Asha Barlowe (2001-2002)
rest of cast listed alphabetically
Malkolm Alburquenque .... Case Smith (2001)
Anita Brown .... Gill Girl
Peter Bryant .... Bling (2000-2001)
Lisa Ann Cabasa .... Tinga/X5-656/Penny Smith
Jenna Marie Gooch .... Eva/X5-766 (2000)
Robert Gossett .... Colonel James 'Jim' McGinnis (2000-2001)
Jesse Hutch .... Gill Guy (2001)
Erin Karpluk .... Gem (2002)
James Kirk .... Young Ben (2001)
Stephen Lee .... Daniel 'Dan' Vogelsang (2000)
William Gregory Lee .... Zack/X5-599 (2000-2001)
Philip MacHale .... Jonathan Bilodeua (2000)
Byron Mann .... Detective Matthew 'Matt' Sung
John Mann .... British Eddy (2001-2002)
Brian Markinson .... Dr. Sam Carr (2001-2002)
Sky Miles .... Sky
Douglas O'Keeffe .... Bruno Anselmo (2000-2001)
Dylan Pearson .... Jack (2000)
Rey-Phillip Santos .... Original Albino X (2001)
Michael Sbrizzi .... Biggs (2002)
Kyley Statham .... Young Jondy (2000)
Nana Visitor .... Dr. Elizabeth Renfro/Madame X (2001)
Alex Zahara .... Johanssen (2000-2001)