The 2008 AFC Champions League was the 27th AFC Champions League, the top-level Asian club football tournament, and the 6th under the current AFC Champions League title. It was the last AFC Champions League before the competition expanded to 32 teams.
Format
Group stage
A total of 28 clubs were divided into seven groups of four, based on region, i.e. East Asian and Southeast Asian clubs were drawn in groups E to G, while the rest were grouped in groups A to D. Each club played double round-robin (home and away) against the other three teams in their group, a total of 6 matches each. Clubs received three points for a win, one point for a draw and no points for a loss. The clubs were ranked according to points and tie breakers were in the following order:
Points earned between the clubs in question
Goal difference between the clubs in question
Goal difference within the group
Goals for within the group
The seven group winners and the defending champion advanced to the quarter-finals.
Knockout stage
All eight clubs were randomly paired together, with the restriction that clubs from the same country could not face each other in the quarter-finals. The games were played over two legs, home and away; the team with the higher aggregate score was declared the match winner. If the aggregate score could not produce a winner, "away goals rule" was used. If the two teams were still tied, extra time was played, at the end of which the "away goals rule" was again applied if the scores were tied. If still tied, the game would go to penalties.
Schedule
Group stage draw - 12 December 2007
Group round: 12–19 March, 9–23 April, 7–21 May
Knockout stage draw - 24 May 2008
Quarter-finals: 17–24 September
Semi-finals: 8–22 October
Final: 5 and 12 November
Participating clubs
Indonesia were initially allocated two entries as per previous years. However, on 12 December 2007, the AFC awarded one to Thailand and the other one to Vietnam because the Indonesian domestic league and cup tournament wouldn't be completed in time for the start of the tournament. Both Thailand and Vietnam therefore effectively recovered the entries they had lost the previous year.