Quarterback Scott Campbell passed for 290 yards and three touchdowns and ran 20 yards for another score as the host Boilermakers dropped Illinois from a tie for first in the Big Ten.
Purdue is 3-2 overall and 1-2 in the conference. Illinois is 3-2 and 2-1.
The Boilermakers, aided y three first-half field goals by Tim Clark, took a 23-14 halftime lead, then shut out Illinois until the final minute of the game.
A 13-yard touchdown pass from Campbell to Everett Pickens, ending a long drive in the third quarter, put the Boilermakers ahead 3-14. Early in the final period, Campbell threw a 30-yard scoring pass to Steve Bryant, whose 17-yard reception set up the previous touchdown.
Purdue's final touchdown came on an 11-yard pass from Campbell to Pickens.
Campbell completed 19 of 29 passes. Pickens finished with eight receptions for 128 yards, and Bryant caught seven passes, all in the second half, for 105 yards.
Campbell scored Purdue's first touchdown early in the game, seven plays after Derrick Taylor intercepted a pass by Illinois' Tony Eason at the Boilermaker 33.
Eason threw a 71-yard scoring pass to Mike Martin in the first half and a 25-yard touchdown pass to Tim McAvoy in the last minute of the game.