Nacional defeated Independiente del Valle in the final to win their first title, while River Plate defeated defending champions São Paulo to finish third.

The competition was contested by 12 teams: the title holders, the youth champions from each of the ten CONMEBOL member associations, and one additional team from the host association.

The draw was held on 25 January 2018, 16:00 UYT (UTC−3), at the headquarters of the Uruguayan Football Association.

The defending champions São Paulo were automatically seeded into Pot 1 and allocated to position A1 in the group stage, while the other two teams which also participated in the 2016 U-20 Copa Libertadores, Independiente del Valle and Libertad, were also seeded into Pot 1 and drawn to position B1 or C1 in the group stage.

If tied on points, tiebreakers were applied in the following order (Regulations Article 20):[1] The winners of each group and the best runner-up among all groups advanced to the semi-finals.