The 2004 Big Ten Conference baseball tournament was held at Siebert Field on the campus of the University of Minnesota in Minneapolis, Minnesota, from May 15 through 19.
The top six teams from the regular season participated in the double-elimination tournament, the twenty third annual tournament sponsored by the Big Ten Conference to determine the league champion.
Minnesota won their eighth tournament championship and earned the Big Ten Conference's automatic bid to the 2004 NCAA Division I baseball tournament.
As in the previous two years, the top two seeds received a single bye, with the four lower seeds playing opening round games.
Teams that lost in the opening round played an elimination game.