Created by Dr. Boynton in the likeness of his deceased son, Astro Boy is a thinking, caring robot with a heart and soul. After being abandoned by his creator, Astro is rescued by Dr. Elefun, who adopts him as his own and guides him in the use of his special powers to aid and protect mankind.

Most memorable for his big nose, Dr. Elefun becomes the head of the Ministry of Science after Dr. Boynton is fired. Elefun rescues Astro from the robot circus and takes him back to Japan. Elefun takes care of Astro until he is able to construct a family for him.

Father of Toby and head of the Ministry of Science. When Toby was killed in a car accident, Boynton created Astro Boy in his son's likeness and raised him as his own child. When this caused him to lose his position at the Ministry of Science, he and Astro went away together on an ocean cruise -- where they became separate during an iceberg emergency.

Astro's school teacher and a good friend of Dr. Elefun. His real name is Albert Duncan (ヒゲオヤジ), but everyone calls him Daddy Walrus.

Astro's parents were built by Dr. Elefun as a family for Astro. They don't have names -- they are simply called "Mom" and "Dad."

Uran is Astro's sister, created as a present by Dr. Elefun. She is a very lively and mischievous girl, who often gets herself and her brother into a lot of trouble.

Jump was Toby's pet dog. After Toby was killed, Jump found it difficult to accept Astro as his new master. But in time, they grew to be close friends, and Jump now lives happily with Astro and his family.

Atlas is Astro's arch-enemy. He was created a short time after Astro, when plans for him were stolen from the Ministry of Science. Atlas lives in the Crystal Castle with Livian, who later discovers that Atlas and Astro were both made from the same plans -- making them brothers.

Livian is Atlas' companion, although she is not evil like him. Livian was alerted many times of Atlas' plans, and is the one to discover that Astro and Atlas are brothers.

Head of the Tokyo Police Department, Inspector Gumshoe is a dedicated police officer who is always eager to get his man. Unfortunately, he has a habit of making snap conclusions and arresting the wrong man -- and too often, that's Astro!

Guiss is an evil scientist and the original creator of Atlas and Livian. He stole the plans for Astro from the Ministry of Science, and used them to create Atlas -- including the "Omega Factor," which made Atlas capable of evil deeds. Atlas later rebelled against his master and rebuilt himself to be more powerful than ever.

Skunk is an escaped criminal -- one of the most wanted in all Japan. Skunk and Astro have crossed paths many times, and Skunk is determined to destroy the young robot for so often foiling his evil schemes.

Son of the son of the son of the infamous Mandrake I. His motto in life is simple: "Get everything I want."