The 2021 Copa Sudamericana group stage was played from 20 April to 27 May 2021.
[2] The draw for the group stage was held on 9 April 2021, 12:00 PYT (UTC−4), at the CONMEBOL Convention Centre in Luque, Paraguay.
[3][4] Teams were seeded by their CONMEBOL Clubs ranking as of 1 February 2021 (shown in parentheses),[5][6] taking into account the following three factors:[7] For the group stage, the 32 teams were drawn into eight groups (Groups A–H) of four containing a team from each of the four pots.
Teams from the same association could not be drawn into the same group, excluding the four losers of the Copa Libertadores third stage, which were seeded in Pot 4 and whose identity was not known at the time of the draw, and could be drawn into the same group with another team from the same association.
[2] The winners of each group advanced to the round of 16 of the final stages.