Monsters, Inc. came to the theatres in 2001. It is the fourth Disney/Pixar movie after "Toy Story", "A Bugs Life" and "Toy Story 2".
Monsters, Inc. soared past the $524 million mark at the worldwide box office and became in 2002 the second highest grossing animated film of all time, behind "The Lion King".

Monsters, Inc. has a lot of references to "Toy Story" and "A Bug's Life". The cloud wallpaper from Andy's room in Toy Story is seen briefly as one of the wallpapers that Randall uses to test his chameleon skills against. When Sulley is about to say goodbye to Boo, Boo is trying to get him to play.

She hands him a Jessie doll from Toy Story 2 as well as Nemo The Clownfish from Finding Nemo. Randall Boggs is last seen in a trailer home. There is a Pizza Planet truck from Toy Story and Toy Story 2 beside the trailer, and the trailer and Pizza Planet truck were also featured in A Bug's Life. The artificial child featured after the beginning credits of the film looks remarkably like Andy from Toy Story. When Boo pulls on the stacked DVDs in Sullivan's apartment and they all come falling down, the DVD she's holding can be seen to be A Bug's Life. When Mike and Sully emerge from the straw house on the beach, the Toy Story cloud is visible in the sky. At the very end, when Mike is talking to Sulley on the Laugh Floor, just before showing him the rebuilt door, a giant version of a pop-up clown toy in Andy's room from Toy Story can be seen behind them.