The 2004 Big Ten men's basketball tournament was the postseason men's basketball tournament for the Big Ten Conference and was played between March 11 and March 14, 2004 at Conseco Fieldhouse in Indianapolis, Indiana.

As a result, Wisconsin received the Big Ten's automatic bid to the NCAA tournament.

It also marked the first time in tournament history that the top two seeds appeared in the championship game.

Teams were seeded by conference record, with a tiebreaker system used to seed teams with identical conference records.

Seeding for the tournament was determined at the close of the regular conference season.