World football's governing body Fifa on Tuesday cleared the format for the first World Cup to boast 48 teams.
The 2026 tournament in Mexico, Canada and the United States will start in June and finish on 19 July.
It will feature a new last-32 knockout round comprising the winners and runners-up of the 12 groups as well as the eight best third-placed teams.
Fifa officials had been weighing up proposals to have 16 groups of three teams with the top two from each pool advancing to the last 32
But the Fifa council meeting in the Rwandan capital Kigali rejected the plan and opted for 12 groups of four national squads.
Change
It is believed the thrilling end to the group phases in Qatar persuaded organisers to retain the four-team configuration for the first phase.
There were also concerns over three-team groups because teams would be unable to finish the pool stages at the same time.
"The revised format mitigates the risk of collusion," said a statement from the Fifa council. "And ensures that all the teams play a minimum of three matches, while providing balanced rest time between competing teams;"
The addition of 16 teams for the 23rd edition of the competition will mean 104 games - 40 more than in Qatar in November and December 2022.
As a result, the finalists, and the teams finishing third and fourth, will play a total of eight games instead of the current seven.
