Qatar's government has abandoned its attempt to move ICAO's headquarters to the Gulf state's capital, Doha.
ICAO members had been set to vote on the proposal at the 38th Assembly which is scheduled to start in September.
"Qatar has withdrawn its offer to serve as the new permanent seat of ICAO," the civil aviation organisation confirms.
Montreal has served as the headquarters of ICAO since 1946.
Canadian foreign minister John Baird says he is "pleased to confirm" the decision by Qatari government authorities to drop the proposal.
Doha is the base for Qatar Airways, which is preparing to transfer operations to the site of a new international hub airport.