The 1989 Big Ten Conference baseball tournament was held at Ray Fisher Stadium on the campus of the University of Michigan in Minneapolis, Minnesota from May 19 through 20. The top four teams from the regular season participated in the double-elimination tournament, the ninth annual tournament sponsored by the Big Ten Conference to determine the league champion. Illinois won their first tournament championship and earned the Big Ten Conference's automatic bid to the 1989 NCAA Division I Baseball Tournament. Illinois was the first team other than Michigan and Minnesota to win the event.