The Japanese version aired on TV Tokyo, consisting out of 51 episodes and with one movie made for the series. The Saban-produced Mon Colle Knights aired on Fox Kids in North America from July 2001 to September 2002, consisting out of 45 episodes. In 2006 it aired on Jetix on Sundays at 10:00 PM. The manga, written by Satoru Akahori and Katsumi Hasegawa and drawn by Hideaki Nishikawa, is published in English in Singapore by Chuang Yi.
 PlotThe series features Mondo Ooya and his girlfriend Rokuna Hiiragi, whose father Professor Ichiroubei Hiiragi invented a way to travel to Mon World (Roku Mon Sekai: the Six Gate World), where all sorts of magical creatures live. Together, they try to find six monster items which, when combined, could connect the Six Gate World with planet Earth for the better of both worlds. Rockna and Mondo form the Mon Colle Knights, and when chanting a phrase they can merge into monsters and control them into battle as well as aid with spells. Almost every episode, they battle Professor Hiiragi's rival Prince Eccentro (Count Collection in the Japanese version) and his two female lackeys Gluko and Batch who are after the same thing as the Mon Colle Knights, except that they intend to use the items to dominate both worlds.
 Main characters
 Mon Colle Knights
- Mondo Ooya (大矢 門斗, Ōya Mondo )
- Voiced by: Tomo Saeki (Japanese), Derek Stephen Prince (English)
- One of the main protagonists of the series. Mondo is an adventurous young boy who seeks to gather the Mon items to bring together his world and Mon world for peace and friendship. Even though he has an outgoing and determined nature, Mondo has a little problem: he always flirts with pretty girls (Beginner, Kahimi and Lailai are the most notable). Note that the first Kanji in Mondo's given name; "Mon (門, Mon )," is the same that is used in the Mon Colle Knights title, Roku Mon Tengai Mon Colle Knight (六門天外モンコレナイ ト, Roku Mon Tengai Mon Kore Naito ). He has devices which he use for his peace sign attack.
- Rockna Hiiragi (柊 六奈, Hiiragi Rokuna )
- Voiced by: Yui Horie (Japanese), Brianne Siddall (English)
- One of the main protagonists of the series. Rockna is Mondo's genius friend, whose intentions match Mondo's. She has a special telepathic ability to communicate with monsters. Now her boyfriend Mondo likes drooling over her, but gets jealous if Mondo flirts with other girls causing Rockna to attack him. The first Kanji in Rockna's given name; "Roku (六, Roku )," is the same that is used in the Mon Colle Knights title, Roku Mon Tengai Mon Kore Naito (六門天外モンコレナイ ト, ''Roku Mon Tengai Mon Kore Naito ). She has a baton like devices which she use for her string or ribbon attack.
- Professor Ichiroubei Hiiragi (柊 一郎兵衛, Hīragi Ichirōbei )
- Voiced by: Shigeru Chiba (Japanese), Jamieson Price (English)
- Rockna's father and a rather eccentric sort of mad scientist. He discovered Mon World and wants the human world to know about it so he can win lots of awards.
- Jāne (ジャーネ, Jāne ) / Lovestar
- Voiced by: Yuko Mizutani (Japanese), Wendee Lee (English)
- Lovestar is a Zeechi that Rockna adopted. A pale pink hamster like monster with a red star marked on her back. In the Japanese version, his species is called "Lovestar" because the sounds the creatures make resemble the word "love-love" and the pattern on their backs make a star. Also in the Japanese version, Lovestar is called "Jāne," because, when Rockna was trying to say goodbye ("Jā ne") to him, Lovestar thought she was calling him by name.
- Punchpunch (パンチパンチ, Panchipanchi )
- Voiced by: Maria Yamamoto
- A tiny monkey monster who punches.
- Professor Hiiragi's chicken-based computer. It usually serves as a computer for Professor Hiiragi and goes off whenever a monster is near.
 Collection team
- Count Ludwig Presto Von Meinstein Collection (ルードヴィヒ・ブレスト・フォン・マインシュタイン・コレクション, Rūdovihi Buresuto Fon Mainshutain Korekushon ) / Prince Ludwig Von Monsterstein Eccentro
- Voiced by: kazuhiko inoue (Japanese), joe ochman (English)
- One of the principle antagonists of the series. Prince Eccentro a young effeminate aristocrat from Europe who wants to take over Mon World. He was trained by Tanaka when his father wanted him to be a bad guy. Not much a threat due to his eccentric behavior and hysterical persona at times. However, he is the inventor of the hypnotic Skeitso Beam (whether on his Flying Lion aircraft or Teddyarenaut) which he uses to bend monsters to his will. Because of that, he tends to have his evil moments, though he really isn't as evil as he brags himself to be. Everytime Prince Eccentro fails, Tanaka would punish him with back-breaking exercises related to the episode's content. His dream is apparently to become a world famous belly-dancer.
- A bear-like computer created by Eccentro. He serves as the counterpart to the Cluckputer and has a built-in Skeitso Beam. In an episode, he develop temporairy an IA, because savant bear think he is their king.
- Batchi (バッチィ, Batchii ) / Batch
- Voiced by: Kyoko Hikami (Japanese), Wendee Lee (English)
- Eccentro's tomboyish lackey. She unfortunately gets punished by Tanaka as well (except in two episodes). She and Eccentro argue a lot but she always obeys him.
- Guko (グーコ, Gūko ) / Gluko
- Voiced by: Yuka Imai (Japanese), Dina Sherman (English)
- Eccentro's busty, yet air-headed and friendly lackey. She tends to be spared by Tanaka when it's time for punishment and has a creepy amount of luck. She never seems to get hurt while the rest of her team and the Mon Colle Knights usually does. An english ongoing joke in the series is that during Eccentro's launch sequence in each episode, she asks a very long and logic based question which ends with Eccentro and Batch becoming bored and saying "Never mind, Gluko." In the Japanese version, Gluko speaks in a very polite and respectful dialect, whether she's talking to her teammates or her enemies. Gluko also carries around a book detaling about Mon World and his creatures. In a later episode, Gluko ends up adopting a Forest Imp named Impy.
- Chuzaemon Takenaka (竹中 忠左衛門, Takenaka Chūzaemon ) / Tanaka