The 1998 U.S. Open Cup ran from June through October, 1998, open to all soccer teams in the United States.
The first-year Major League Soccer club Chicago Fire won the Cup with a 2–1 overtime victory over the Columbus Crew at Soldier Field in Chicago, Illinois.
In the early rounds of the tournament, only one MLS team lost to a minor-league side, when the A-League's Nashville Metros beat the Kansas City Wizards 3–1.
Home teams listed on top of bracket
Eight D3 Pro, four PDL, and four USASA teams start.
Eight A-League enter.
Eight MLS enter.