The 2003 Copa Nissan Sudamericana was the second edition of CONMEBOL's new international club tournament. It was won by Peruvian club Cienciano, who won the first international trophy for their club and the country. They also qualified to play in the 2004 Recopa Sudamericana.

First stage

Argentina Preliminary

!colspan="5"|Argentina III Preliminary !colspan="5"|Argentina IV Preliminary

Brazil Preliminary

Brazil 1 Preliminary

Brazil 2 Preliminary

Brazil 3 Preliminary

Brazil 4 Preliminary

Venezuela/Bolivia/2002 Champion Preliminary

First round

!colspan="5"|Venezuela Preliminary

Second round

!colspan="5"|Venezuela/San Lorenzo Preliminary !colspan="5"|Bolivia Preliminary

Peru/Chile Preliminary

!colspan="5"|Chile Preliminary !colspan="5"|Peru Preliminary

Colombia/Ecuador Preliminary

!colspan="5"|Colombia Preliminary !colspan="5"|Ecuador Preliminary

Paraguay/Uruguay Preliminary

!colspan="5"|Paraguay Preliminary !colspan="5"|Uruguay Preliminary

Second stage

Argentina Zone

!colspan="5"|Quarterfinalist 4 !colspan="5"|Quarterfinalist 8

Brazil Zone

!colspan="5"|Quarterfinalist 2 !colspan="5"|Quarterfinalist 5

Venezuela/Bolivia/2002 Champion Zone

!colspan="5"|Quarterfinalist 6

Peru/Chile Zone

!colspan="5"|Quarterfinalist 1

Colombia/Ecuador Zone

!colspan="5"|Quarterfinalist 3

Paraguay/Uruguay Zone

!colspan="5"|Quarterfinalist 7

Bracket

Quarterfinals

Semifinals

Finals