The World Cup will be expanded to host 48 teams, up from 32, Fifa has decided.
An initial stage of 16 groups of three teams will precede a knockout stage for the remaining 32 when the change is made for the 2026 tournament.
The sport’s world governing body voted unanimously in favour of the change at a meeting in Zurich on Tuesday.
The number of tournament matches will rise to 80, from 64, but the eventual winners will still play only seven games.
The tournament will be completed within 32 days – a measure to appease powerful European clubs, who objected to reform because of a crowded international schedule.
The changes mark the first World Cup expansion since 1998.
Why expand? ‘Football is more than just Europe and South America’
Fifa president Gianni Infantino has been behind the move, saying the World Cup has to be “more inclusive”.
“We are in the 21st century and we have to shape the World Cup of the 21st century,” he said at a news conference after the announcement.
“It is the future. Football is more than just Europe and South America, football is global.
“The football fever you have in a country that qualifies for the World Cup is the biggest promotional tool for football you can have.
“This football promotion, in many parts of the world where today they have no chance to play [at the World Cup], was at the top of our thoughts.”
According to Fifa research, revenue is predicted to increase to £5.29bn for a 48-team tournament, giving a potential profit rise of £521m, although Infantino says it was a football-based move.
He says the decision on who will get the extra qualification slots has yet to be decided but “this will be looked at speedily”.
“No guarantees have been made,” he added. “The only sure thing is that everyone will have a bit more [representation] than they have.”
He says there is no rush to decide what will be used to separate teams who finish on the same points and goal difference. Reports had suggested there could be a penalty shootout at the end of each drawn match.
But Infantino said: “This will be part of the regulations to be decided a few years before the event, it is nothing for now.”