2004 Major League Soccer season

The 2004 Major League Soccer season was the ninth season of Major League Soccer. It was also the 92nd season of FIFA-sanctioned soccer in the United States, and the 26th with a national first-division league.

After playing one season in the suburb of Southlake, the Dallas Burn returned to the Cotton Bowl.

D.C. United signed 14-year-old prodigy Freddy Adu, who made his debut as a substitute in their season opener becoming the youngest player in North American sports history. The Columbus Crew emerged as a dominant team in the second half of the regular season, running off an MLS-record 18-game unbeaten streak en route to winning the Supporters' Shield.

The regular season began on April 3, and concluded on October 17. The 2004 MLS Cup Playoffs began on October 22, and concluded with MLS Cup 2004 on November 14. D.C. United won their record 4th league title by defeating the Kansas City Wizards in MLS Cup.

Season format
The season began on April 3 and concluded with MLS Cup on November 14. The 10 teams were split evenly into two conferences. Each team played 30 games that were evenly divided between home and away. Each team played every other team in their conference, and two designated opponents from the opposite conference, four times, and the remaining teams in the opposite conference twice.

The top four teams from each conference qualified for the MLS Cup Playoffs. In the first round, aggregate goals over two matches determined the winners. The conference finals were played as a single match, and the winners advanced to MLS Cup. In all rounds, draws were broken with two 15-minute periods of extra time, followed by penalty kicks if necessary. The away goals rule was not used in any round.

The team with the most points in the regular season was awarded the MLS Supporters' Shield. Additionally, the winner of MLS Cup and the runner-up qualified for the CONCACAF Champions' Cup.

Conference semifinals
''New England Revolution advance 2–1 on aggregate.

D.C. United advance 4–0 on aggregate.

Kansas City Wizards advance 3–2 on aggregate.

Los Angeles Galaxy advance 2–1 on aggregate.

Conference finals
D.C. United advance 4–3 on penalties (3–3 after full time).