The 2012 London Olympics will have only 26 sports after baseball and softball were axed from the programme on Friday.
They are the first sports to be cut from the Games in 69 years and it means Regents Park, which was due to host them, will no longer be a 2012 venue.
Squash and karate were initially nominated as their replacements but neither polled enough IOC members' votes to win a place at the Games.
Rugby union sevens, golf and roller skating were also in the running.
International Olympic Committee members went through seven rounds of voting to decide which two of the five sports should be put up for a vote to give them Olympic status.
Squash and karate were chosen, but not enough of the IOC members wanted them to be included. It means the earliest they can now be introduced into the Games is 2016.
International Olympic Committee members held a secret ballot to decide which sports to axe from the existing list of 28 ahead of the London Games in 2012.
Baseball and softball, which will remain on the Olympic programme for 2008, failed to get enough votes.
They are the first sports to be cut from the Olympics since polo in 1936.
The decision to exclude baseball and softball should save London at least £50m, as well as meaning Regents Park will not be used as a venue.
"Regents Park will cease to be an Olympic venue but it could be used to help stage our cultural celebrations during the Games," 2012 spokesman Mike Lee said.
He added: "We are delighted to be delivering the Olympic and Paralympic Games, whatever the size of the programme."
"This is a matter for the IOC and we will deliver whatever range of sports they decide."
Baseball made its first appearance in the 1992 Games, although it was only in 2000 that professional players were allowed to take part.
Softball was introduced in Atlanta in 1996 and has been dominated by the United States, who have won all three gold medals to be contested.
IOC president Jacques Rogge said baseball and softball could win back their place for future games.
"Needless to say, these sports are very, very disappointed, but it does not disqualify them forever as Olympic sports," he said.