Boo's teddy bear is the same bear as the one seen on the shelf in the simulator bedroom.
Bob Peterson, the movie's story supervisor, provided the temporary voice of Roz, the green secretary, during production. The nasal, sing-song voice proved to be such a success that they kept it in the final film.
# # The design of Mike is based on a Halloween costume inventor 'Doug Malewicki' designed for his daughter Michelle, which was featured on an edition of 'Pee-Wee's Playhouse.
Mary Gibbs was so young that it proved difficult to get her to stand in the recording studio and act her lines. Instead, they simply followed her around with a microphone and cut Boo's lines together from the things she said while she played.
The newspaper article concerning Boo's appearance in Harryhausen restaurant, though briefly seen, is actually readable and fully written in complete English.
In the German dubbing of the film, the Yeti speaks the Swabian dialect, which is mostly spoken in south-western Germany, and makes a reference to wishing he had banished to the Swabian Alb where he has friends.
In keeping with the running gag of Mike being obscured in every photo, on the DVD the hole in the disc appears directly over where Mike would be standing.
The items on sale at the Grossery include Mangle Fruit, Bilge Berries, and Blood Oranges - which is a real kind of orange.
The animators originally drew tentacles instead of legs for Sulley. However, they decided to use legs because they believed the audience would concentrate more on the tentacles than Sulley's face.
According to the original character design sketches found on the DVD, Fungus's first name is Jeff and his surname was originally "Frungus".
# # The animators considered giving Sulley tentacles instead of legs at one point, and glasses at another. They also considered making Mike arm-less with only legs.
It normally took 11 to 12 hours to render a single frame of Sulley because of his 2.3 million individually animated hair strands.
The three ads at the end of the company play, "Put That Thing Back Where It Came From, Or So Help Me!" are for Tony's Grossery (seen earlier in the movie when Mike and Sulley pass it), Pixar Shorts ("We've got the important things covered") and Pete's Barber Shop (specializing in/selling Claw Wax, Scale Polish, and Mange Management).
When Sulley and Mike are walking to work, they go pass "Tony's Grossery".
When Boo is in the bathroom stall she "sings" two songs. The first one is to the tune of Beauty and the Beast (1991), another Disney movie. The second one is to the tune of "One Love", from Snow White and the Seven Dwarfs (1937).