The university, where Ayers' wife Bernardine Dohrn teaches at the law school, gave no reason for the cancellation. Ayers had been invited by a Muslim student group, the Chicago Tribune reported.
Alan Cubbage, vice president for university relations, said that the talk hasn't been rescheduled.
Ayers, a professor of education at the University of Illinois and education activist in Chicago, has been busy this week. He became something of an issue during the presidential campaign because President-elect Barack Obama served on a board with him in Chicago and Ayers hosted a fundraiser several years ago for Obama.
On Monday, Ayers talked at Georgetown University law school in Washington and at a Washington church. That appearance was transferred from a book store because the crowd was so large.
Ayers was interviewed Tuesday on NPR's "Fresh Air." He boasted that whenever Republican nominees John McCain and Sarah Palin brought him up their poll numbers went down.
His book "Fugitive Days," has been reissued in paperback.