See main article: 2003 MercedesCup.
Mikhail Youzhny was the defending champion but lost in the quarterfinals to Guillermo Coria.
Coria won in the final 6–2, 6–2, 6–1 against Tommy Robredo.
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated. All sixteen seeds received a bye to the second round.