New voter cards will appear in the mail over the next few days. About 300,000 voters are affected.
Changes will be in place for the November 6th general election.
"It's critical that our voters make sure they are informed so when election day comes, first of all they go to the right place, and that they vote within the right political boundaries," said Langdon Neal, chairman of the Chicago Board of Election Commissioners.
The number of precincts has been reduced by more than 20 percent; that is expected to save voters about $1 million a year.