Shinichi Kudo: Shinichi is a 17 year old high school detective. He is the son of the famous author Yuusaku Kudo, and the famous actress Yukiko Kudo. When he was around 14 years old, his parents moved to the USA. Shinichi is quite arrogant, but he is also a very kind person, he would go through hell to save the persons he cares for.

Conan Edogawa: Conan is Shinichi after he got shrunk. His body was small but his brain stayed the same. His small body annoys him, and he only thinks of getting his old one back again. Conan solves the cases for Kogoro, he shoots him in the neck with his stun gun wrist watch, and when Kogoro falls asleep, Conan immitates his voice via his bowtie. He is member of the Detective Boys, wich is a little groups of child detectives.
Age: 7 (17)

Ran Mouri: Ran is Shinichi's "girlfriend". They have know each other since their childhood, and are still very good friends. Ran is a karate champion, just like Shinichi is a soccer player. She is a very sensitive girl, but if someone touches her at the wrong place, she can get very mad. Ran keeps waiting for Shinichi, and sometimes she stayes up till late night and thinks of only him...   
Age: 17

Kogoro Mouri: Kogoro is Ran's father. He was once a police officer, but because he "accidently" shot at his wife, he was suspended. Now he is a famous private detective. But Kogoro doesn't know that Conan is behind it all... Kogoro drinks and smokes a lot, and he's crazy about the famous singer Yoko Okino, and he's also a horse race fan. Even if he acts stupid sometimes, he is a quite clever person, and he would go through hell to save his daughter, Ran. 
Age: 37

Dr. Agasa: Agasa is the neighbour and friend of Shinichi, who helped him when he got shrunk. He's an inventor and loves to experiantate with stuff. He has no wife and no children, but he loves children. He is also a good friend and helper of The Detective Boys gang.  
Age: 52

Ai Haibara/Shiho Miyano/Sherry: Ai is a classmate of Conan. Just like Conan, she got shrunk by the APTX4869 pill. She was a member of The Black Orgnization, and had developed the drug because she was told to. But after they killed her sister, she quit. When she knew she was going to die, she shallowed the drug. The drug made her body shrink just like Shinichi, and now she lived with Dr. Agasa, and is the 5th member of The detective Boys. 
Age: 18

The Detective Boys Gang: Ayumi Yoshida, Mitshiko Tsubaraya and Genta Kojima are members of The Detective Boys, together with Conan and Ai. Both Genta and Mitsuhiko have a crush on ayumi, but she seems to like Conan, wich makes the two boys jealous. They're not as clever as Conan, but they're not stupid because of that. They love adventures, and they get involved in crimes all the time.   
Ages: 7

Sonoko Suzuki: Sonoko is Ran's best friend. Sonoko's parents are very rich, maybe that's why Sonoko is a bit snobbish sometimes. she loves boys, and she always searches for a boyfriend. Sonoko is quite a smart girl, but she's pretty easy to scare as well.  
Age: 17

Heiji Hattori and Kazuha Toyama: Heiji Hattori is a high school detective from Osaka. When he first appears, he's like a rival to Shinichi, but now the two of them are the best friends. Heiji is almost as clever as Shincihi, and also pretty arrogant sometimes. His father is a policeman - the superintendent of Osaka. Heiji has known Kazuha since the kindergarten, and they are very good friends. Kazuha is also his neighbour, and her father is lieutenant at the police in Osaka. Heiji does Kendo, and he's nr2 in the entire region ( behind Okita - Yaiba's rival). Kazuha has a second dan in Aikido ( to give you an idea its two ranks above black belt)  
Ages: 17

Eri Kisaki: Eri is Ran's mother. She's a famous and beloved lawyer, but her relationship with Kogoro isn't that good anymore. After he shot her, she left both him and Ran, now she only wants to see Ran. Her cooking skills are very bad, tough she would never admit that. She says she hates Kogoro like hell, but actually, she still likes him a lot. 
Age: 37

Yuusaku Kudo: Yuusaku is Shinichi's father. He's a famous mystery novelist. Shinichi inherited his intelligence from his father, who also used to be a high school detective once. Due to his knowledge Yuusaku is quite arrogant like Shinichi, he's a smoker, and (probably)  likes women just like Kogoro. 
Age: 37

Yukiko Kudo: Yukiko is Shinichi's mother. She used to be a world famous actress, who has made movies. She's not arrogant like Yuusaku, but she doesn't like when people talk bad about her. She cares a lot about her look, and when Conan calls her aunt, she tells him to call him nice young lady. Yukiko best friend is Sharon Vineyard, who really is Vermouth, a member of the Black Organization. Yukiko also likes to be VERY dramatic.
Age: 37

The Police of Tokyo: Inspector Megure, officer Sato, Takagi and Shiratori are the policemen you see the most in DC. Megure is an old friend of Kogoro, they worked together when Kogoro was still in the police force. Takagi and Sato are the "police love pair", they are secretly in love with each other, but Shiratori also seems to like Sato, so he and Takagi are rivals in that point. Yumi from the "traffic section" is also a well known officer. Ages: unknown.

Tomoaki Araide: We know him from the episode where his father gets killed.. He is a young doctor that also works as basketball coach near Teitan High School which Ran goes to. Vermouth disguised herself as Dr. Araide while he was in another city. Jodie and her friends made it look like to Vermouth, that Araide had died in a caraccident. But in the Halloween party Episode, Vermouth finally revealed herself. Dr. Araide seems to like Hikaru (from the episode he appeared) a lot, and he also seems to like Ran. Ran seemed to have liked him too, making Conan jalous.  
Age: 25