The format of ICC Champions Trophy has undergone a lot of changes since its inception.

Champions Trophy Format

ICC Champions Trophy is considered to be the second most important cricket tournament, in context of One Day Internationals, next only to the World Cup. However unlike the World Cup, this championship takes place every two years and the whole tournament is over within a period of somewhere around two weeks. The format of the Cricket Champions Trophy has undergone significant changes since its inception, in the year 1998.

Initial Tournaments
In the first four tournaments i.e. Champions Trophy 1998, 2000, 2002 and 2004, a total of twelve teams participated, including all the ten full members of the International Cricket Council (ICC) and two associate members. The Champions Trophy of 1998 and 2000 were Knock Out Tournaments. There were no pools and the loser in each game was straight out of the tournament. The team that remained in the end was the winner. In 1998, only 8 games were played and 2000 saw the teams playing 10 games.

Champions Trophy 2002 and 2004
In 2002 and 2004, the participating teams were divided into four pools, with three members in each of them. After playing round robin games, it was the top team in each pool that got the chance to play in the semi-finals. The 2006 Champions Trophy had only ten participating teams, which excluded the two associate members. The teams were divided into two pools, comprising of four members each. The two tops teams in each pool played the semi-finals. In this format, losing even one of the matches meant that the team was out of the game.

Champions Trophy 2009
From 2009, the number of participating teams in the Mini World Cup has been brought down to eight. The teams will comprise of the 8 highest-ranked ODI teams, as placed 6 months out from the tournament. The teams have been divided into two groups: Group A and Group B. Each of the teams will play with the other members in its group once and then the two top teams in each of the two groups will move over to semi-finals, the winners of which will play against each other in the finals.