Doraemon is sent back in time by Nobita Nobi's great-great grandson Sewashi to improve Nobita's circumstances so that his descendants may enjoy a better future. In the original timeline, Nobita experienced nothing but misery and misfortune throughout his life. As a result of this, Nobita's failures in school and always gets 0 marks in his tests. and subsequently, his career, have left his family line beset with financial problems. In order to alter history and better the Nobi family's fortunes, Sewashi sent him a robot called Doraemon.

Doraemon has a pocket from which he produces many gadgets, medicines, and tools from the future. The pocket is called yojigen-pocket, or fourth-dimensional pocket. Some of the gadgets are based on real Japanese household devices with fanciful twists, but most are completely science fiction (although some may be based on folklore or religious stories). Thousands of dōgu have been featured inDoraemon. The number of dōgu has been approximated at 4,500. It is this constant variety which makes Doraemon popular even among adult readers/viewers. In the series, the availability of dogu depends sometimes on the money Doraemon has available, and he often says some dogu are expensive in the future. The more famous ones include the "bamboo-copter", a small head accessory that allows flight; the "Anywhere Door", a door that opens up to any place the user wishes; and the "Time Machine".

Although he can hear perfectly well, Doraemon has no ears: his robotic ears were eaten by a mouse, giving him a series-long phobia of the creatures.

The stories are formulaic, usually focused on the everyday struggles of fifth grader Nobita, the protagonist of the story. In a typical chapter, Nobita comes home crying about a problem he faces in school and/or the local neighborhood. After hearing him out, Doraemon often offers helpful advice to his problem, but that's never enough for Nobita, who is consistently looking for the "quick, easy" way out (which offers insight to the viewers as to why Nobita's life turned out the way it did). Finally, after Nobita's pleading and/or goading, Doraemon produces a futuristic gadget out of his aforementioned pouch to help Nobita fix his problem, enact revenge, or flaunt to his friends. The only main female character is Shizuka Minamoto (Minamoto Shizuka), who serves as a semi-romantic girlfriend of Nobita, but otherwise a supporting, minor character. Nobita's main human friends include Gian, a known mean bad bully and Suneo, a gloating rich spoiled wealthy kid. There are many recurring supporting characters, such as Dekisugi, Nobita's parents, his school teacher, his descendants from the future, and Doraemon's small sister, Dorami.

Nobita usually goes too far, despite Doraemon's best intentions and warnings, and gets into deeper trouble than before. Sometimes, Nobita's friends (usually Suneo or Gian) steal doraemons gadgets and end up misusing them. However, by the end of the story, there is usually retribution to the characters who end up misusing them, and a moral is taught. Whatever happening in the episodes dosen't happen in the real world.