The 1990 United States Open Cup is the 77th edition of the tournament to crown the national champion of the United States.
The A.A.C. Eagles (MSL) of Chicago won the cup 2–1 against the Brooklyn Italians (NESSL) at Kuntz Stadium in Indianapolis, Indiana.
Bracket
Regional semifinals
I Philadelphia United German-Hungarians (PA) 4-2 Acton Colonials (MA) I Brooklyn Italians (NY) 3-1 Beadling Blues (PA) II A.A.C. Eagles(IL) 1-0 Madison 56ers (WI) II Mike Duffy's (MO) 3-1 Craftsman Paint (MO) III FC Dallas(TX) 2-1 Houston Meadows (TX) III St. Petersburg Kickers (FL) 4-1 Atlanta Datagraphic (GA) IV San Francisco Greek-American (CA) 1-0 Washington Fatigues (WA) IV Los Angeles Zamora (CA) 2-1 OT Colorado Comets (CO)