FIFA President Gianni Infantino had proposed expanding the tournament but the sport's world ruling body said in statement: "Following a thorough and comprehensive consultation process with the involvement of all the relevant stakeholders, it was concluded that under the current circumstances such a proposal could not be made now."
The 2026 World Cup, to be held in the United States, Canada and Mexico, is scheduled to feature 48 teams.
FIFA and Qatar also looked at whether the Gulf state could host an expanded tournament alone by changing the normal requirements for facilities.
"A joint analysis, in this respect, concluded that due to the advanced stage of preparations and the need for a detailed assessment of the potential logistical impact on the host country, more time would be required and a decision could not be taken before the deadline of June," said the FIFA statement.
"It was therefore decided not to further pursue this option."
Infantino began to back away from the idea in March when after a FIFA Council meeting in Miami he said: “If it happens — fantastic. If it doesn’t happen — fantastic also”.
The 2026 World Cup, to be held in the United States, Canada and Mexico, is scheduled to feature 48 teams and given the large number of stadiums available is unlikely to face any logistical problems.
The obstacles to a 48-team tournament in Qatar were numerous and some of the natural partners for joint-hosting in the Gulf were ruled out due to a deep political and economic rift in the region.
The United Arab Emirates, Saudi Arabia, Bahrain and non-Gulf state Egypt cut political, trade and transport ties with Qatar in June, 2017. Those countries accuse Qatar of supporting terrorism, which it denies.
FIFA’s study said the blockade would need to be lifted before there was any chance of those countries hosting matches.
The Qatar World Cup organisers were not immediately available for comment.