The 2004–05 ULEB Cup was the third season of the second-tier level European professional club basketball competition, the EuroCup, which is organized by the Euroleague Basketball Company. The season started on November 9, 2004, and officially ended on April 19, 2005. The second-tier level EuroCup is the European-wide league level that is one tier below the EuroLeague level. Lietuvos rytas won the trophy, by defeating Makedonikos in the final, by a score of 78–74.
Each group contained 6 teams. There were 7 groups. Each team would play amongst each group twice. Top 2 teams from groups A, C, E, F, and G qualify to eighthfinals. Top 3 teams from groups B and D also qualify to the eighthfinals.
In eighthfinals, each team plays against their selected team twice. The winner of the two games with a higher combined score qualifies to quarterfinals. This procedure repeats in quarterfinals and in semifinals.
Regular season
Key to colors
Top two places in each group, plus highest-ranked third-place team, advance to Top 16