The 1998 Major League Soccer season was the third season of Major League Soccer. It was also the 86th season of FIFA-sanctioned soccer in the United States, and the 20th with a national first-division league.
The Chicago Fire and Miami Fusion played their inaugural seasons as the league's first two expansion teams.
The NY/NJ MetroStars dropped the New York/New Jersey from their name and rebranded as just MetroStars, with no city, state or regional name attached to it.
The regular season began on March 15, and concluded on September 27. The MLS Cup Playoffs began on September 30, and concluded with MLS Cup on October 25. Chicago became the first expansion team to win MLS Cup and the first to win it in its inaugural season.
The season began on March 15 and concluded with MLS Cup on October 25. The 12 teams were split evenly into two conferences. Each team played 32 games that were evenly divided between home and away. Each team played every other team in their conference four times, for a total of 20 games. The remaining schedule consisted of two games against each team from the opposite conference.
The top four teams from each conference qualified for the MLS Cup Playoffs. The conference semifinals and finals were played as a best-of-three series, and the winners advanced to MLS Cup. In all rounds, draws were broken by penalty shootout 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 and qualified automatically for the CONCACAF Champions' Cup. Additionally, the winner of MLS Cup, and the runner-up, also qualified for the Champions' Cup.