The 2003–04 FIBA Europe Cup was the second season of the FIBA Europe Cup. After its first season as FIBA's revived' Champions Cup the competition was renamed and now considered Europe's fourth level professional club basketball tournament. However it kept the previous competition system dividing the teams in conferences and the three top teams would now automatically qualify to FIBA Europe League 's following season.
The season started on 5 November 2003, and ended on 28 March 2004. A total number of 41 teams participated in the competition.
The pan-European Final Four was held in the İzmir Atatürk Sports Hall in İzmir. The semifinals were played on 27 March while the Final and third place game were played on 28 March 2017.