A spokesman says the Illinois State Board of Elections received Ryan's withdrawal papers Thursday morning in Springfield.
Ryan's exit comes a day after Republican leaders said they were tired of waiting for him to get off the ballot. They scheduled a meeting next week of the committee that will choose a replacement to face Democrat Barack Obama in the November election.
Illinois Republican Party chairwoman Judy Baar Topinka didn't respond to a request for comment Thursday.
Ryan also didn't return calls seeking comment on his withdrawal, and workers at his campaign office declined to comment.