The 1990 MAC men's basketball tournament took place March 9–11, 1990, at Cobo Arena in Detroit, Michigan.
Ball State defeated Central Michigan, 78–56 in the championship game, to win its second straight (4th overall) MAC Tournament title.
The Cardinals then knocked off Louisville, 62–60, to make the first Sweet Sixteen appearance in program history.
Though their cinderella run would end, Ball State was up to the challenge, falling to No.
Eight of nine conference members participated, with Western Michigan left out of the competition due to their last place finish in the regular season standings.