Mario Kart 64 features eight playable characters, as the original game did. From the original line-up Donkey Kong Jr. and Koopa Troopa were dropped in favour of Donkey Kong and Wario. Kamek was originally intended to appear as a playable character but was replaced by Donkey Kong. The characters can be grouped into three types: Lightweight, Middleweight and Heavyweight.
Lakitu returns as the track marshal and is not a playable character.
Lightweights
They typically have the quickest acceleration and best speed but this is balanced by their poor handling and their vulnerability to being hit by heavier racers. Always use one of these characters in Time Trial mode.
Peach
Toad
Yoshi
Middleweights
Similar to heavyweights, they have poor acceleration and speed, the only differences are their lighter weight.
Mario
Luigi
Heavyweights
They have the best handling and can barge smaller karts out of the way but they also have poor acceleration and low top speed.
Donkey Kong
Donkey Kong in the game, a way to trip him up is to throw down some bananas, he will spin out of control for a little while.