1989–90 League of Ireland First Division
The 1989–90 League of Ireland First Division season was the fifth season of the League of Ireland First Division.Overview
The First Division was contested by 10 teams and Waterford United F.C. won the division.After Waterford United and Sligo Rovers finished level on points, a play-off was held to decide the overall title winners.Waterford United won 2–1 on aggregate and were declared champions.