The 1975 Copa Libertadores group stage or 1975 Copa Libertadores first stage was played from 16 February to 11 April 1975. A total of 20 teams competed in the group stage to decide 5 places in the semi-finals of the 1975 Copa Libertadores, where they joined Independiente, who qualified directly to the semi-finals as defending champions.[1]
The 20 participating teams were divided into 5 groups of 4, which consisted of two teams from one national association and two teams from another.
In the group stage, each group was played on a home-and-away round-robin basis. The teams were ranked according to the following criteria: 1. Points (2 points for a win, 1 point for a draw, and 0 points for a loss); 2. Goal difference
If two teams from the same national association tie on points, the above criteria would not apply and their final positions would be determined in an extra match to be played at a venue within their own country that was decided by drawing of lots. Winners of this match qualified for the seminfinals; in the event of a draw, the team with the best goal difference in the group would have qualified.
The winners of each group advanced to the semi-finals.