Astro Boy / Atom (50 episodes, 2003-2004)
Dr. Ochanomizu (50 episodes, 2003-2004)
Shibugaki (50 episodes, 2003-2004)
Inspector Tawashi (27 episodes, 2003-2004)
Yuko Kisaragi / Steward Robo (23 episodes, 2003-2004)
Uran (18 episodes, 2003-2004)
Dr. Tenma (17 episodes, 2003-2004)
Mr. Lamp (12 episodes, 2003-2004)
Blue Knight (10 episodes, 2004)
Dr. Kato / Kip (7 episodes, 2003-2004)
Additional Voices / Mimi (7 episodes, 2003-2004)
Skunk Kusai (5 episodes, 2003-2004)
Atlas (5 episodes, 2003-2004)
Pluto (4 episodes, 2003-2004)
Shunsaku Kisaragi (4 episodes, 2003-2004)
Nyanko (4 episodes, 2003)
Duke Red (4 episodes, 2004)
Ham Egg (2 episodes, 2003-2004)
Dr. Mini Mini (2 episodes, 2003-2004)
Man A / Solo (2 episodes, 2004)
Bulda's subordinate B / Man C (2 episodes, 2004)
Mimi (1 episode, 2003)
Narrator (1 episode, 2003)
Gulliver (1 episode, 2004)
Marukabi Boon (1 episode, 2004)
Rino (1 episode, 2004)
Sedo (1 episode, 2004)
Kaaya (1 episode, 2004)
Jiro (1 episode, 2004)
Shibugaki (1 episode, 2004)
Tamao (1 episode, 2004)
Donpa (1 episode, 2004)
Dr. Kisaragi (1 episode, 2004)
Kenichi (1 episode, 2004)
Bulda's subordinate A (1 episode, 2004)
Man B (1 episode, 2004)
Dr. Bulda (1 episode, 2004)
Astro Boy (unknown episodes)
Dr. O'Shay, Skunk, Blue Knight, Wally Kisagari, Katari, Harley, Kato, Additional Voices (unknown episodes)
Tawashi (unknown episodes)
Zoran (unknown episodes)
Tenma (unknown episodes)
Matthew (unknown episodes)
Atlas (unknown episodes)
Abercrombie (unknown episodes)
Alejo, Additional Voices (unknown episodes)
Nora (unknown episodes)
Additional Voices (unknown episodes)
Yuko (unknown episodes)