The episode is being hosted by Sanders impersonator Larry David.
Rep. Loretta Sanchez (D-Calif.) said he should not host the show because "racism isn't funny."
The retired neurosurgeon says he doesn't want to put the presidency "in the lightness of comedy."
The GOP front-runner will book a visit on a later date, a Trump spokeswoman said.
"Saturday Night Live" took aim at the controversies surrounding the Mandela memorial service.