MLS adopted a new format for qualification into the playoffs. In 2007, the top two teams from each of the league's two conferences, followed by the next four teams with the highest number of points at the end of the regular season, qualified for the postseason, leading to the possibility of an uneven number of playoff teams from each conference. This year, five teams qualified from the Eastern Conference, and only three teams from the Western Conference qualified, so the Kansas City Wizards, who have been assigned to the Western Conference playoffs, could have played a fellow Eastern Conference team in the final.
The Houston Dynamo, for the second consecutive year in the club's two-year history, won the Western Conference Championship. Their win came through their victories over in-state rival FC Dallas in the conference semifinals and the Kansas City Wizards in the conference championship game. The Dynamo advanced to a rematch against the Revolution, and the MLS Cup, for the second straight year.