The man soon to become the Democratic presidential nominee served with Ayers on an education reform group, the Chicago Annenberg Challenge, during the 1990s.
Files detailing activities of the panel were made available to the media Tuesday after being restricted by the Daley Library at the University of Illinois in Chicago.
The UIC records show that Obama and Ayers attended board meetings, retreats and at least one news conference together as the program got under way, the Chicago Tribune reported Wednesday.
The two continued to attend meetings together during the 1995-2001 operation of the program, the Tribune says.
Ayers was a founder of the Weather Underground, a Vietnam-era anti-war group that claimed responsibility for several bombings.
Ayers spent years in hiding and is currently an education professor.