The Copa Libertadores 1990 was the 31st edition of the most important South American football competition for club teams. 19 teams took part. Colombia was excluded from the tournament in the 1989 Copa Libertadores due to threats against referees by members of the country's drug mafia , so that only defending champion Atlético Nacional was eligible, which also had to play its home games in Chile. The national champions of the CONMEBOL countries and the runners-up took part. Defending champion Atlético Nacional completed the field of participants . The tournament began on February 25th and ended on October 10th, 1990 with the final second leg. The Paraguayan representative Club Olimpia won the final against Barcelona Sporting Club and thus the Copa Libertadores for the second time .
Due to the suspension of the Colombian clubs, Club Olimpia had a bye in the round of 16, as the club, as the winner of Group 5, should meet the third of Group 2. However, after Colombia was excluded, only two teams played in Group 2.