The Organisation for the Prohibition of Chemical Weapons has won the 2013 Nobel Peace Prize.
Experts from the Hague-based global chemical weapons watchdog, supported by the United Nations, are working to destroy Syria's massive chemical weapons stockpile.
Set up in 1997 to eliminate all chemicals weapons worldwide, its mission gained critical importance this year after a sarin gas strike in the suburbs of Damascus killed more than 1,400 people.
Making the announcement in Oslo, Chairman of the Norwegian Nobel Committee Thorbjørn Jagland said the OPCW was not given the prize because of its work in Syria.
He said: "It is because of its long-standing efforts to eliminate chemical weapons and that we are now to about to reach the goal to do away with a whole category of weapons of mass destruction.
"That would be a great event in history if we can achieve that.
"Of course Syria has highlighted the terrible role of these weapons."
Mr Jagland said the award was a reminder to nations with big stocks, such as the United States and Russia, to get rid of their own reserves "especially because they are demanding that others do the same".
Over 250 names were put forward for nomination, including Pakistani schoolgirl Malala Yousafzai, who was shot in the head by the Taliban last year for demanding education for girls.
Asked whether Malala missed out on the prize because of her age, Mr Jagland said the committee never comments on those who do not win the award.
He said: "There were a number of very good candidates but only one can get the prize."
Mr Jagland said there were no formal limitations on the age of the winner.
Tánaiste and Minister for Foreign Affairs and Trade Eamon Gilmore has congratulated the OPCW.
He said: "I was pleased to announce funding last month of €200,000 to support the OPCW's crucial task of destroying chemical weapons in Syria, where the organisation has demonstrated great leadership, efficiency and effectiveness.
"We must never forget that the ultimate goal of disarmament, as embodied in the OPCW, is to save lives and protect civilians."
The award marks a return to the classical disarmament roots of the prize after some recent awards, such as to the European Union last year and US President Barack Obama in 2009.
The Nobel Prize consists of a gold medal, a diploma, and a cash prize of €925,000.
Norwegian public broadcaster NRK, which has a strong track record of leaking the names of winners, reported the OPCW's victory more than an hour before the official announcement.
Higgs 'delighted' with physics prize
Meanwhile, Nobel Prize-winning scientist Professor Peter Higgs has revealed he first heard he won the prestigious award for physics when a woman stopped to congratulate him in the street.
Prof Higgs said a former neighbour, the widow of a judge, got out of her car in Edinburgh as he was returning from lunch and introduced herself.
"She congratulated me on the news and I said 'oh, what news?'" he told a press conference at the University of Edinburgh.
"She told me her daughter phoned from London to alert her to the fact I had got this prize.
"I heard more about it obviously when I got home and started reading the messages."
Prof Higgs was recognised by the Royal Swedish Academy of Sciences for his work on the theory of the particle which shares his name, the Higgs boson.
The existence of the so-called 'God particle', said to give matter its substance, or mass, was proved 50 years on by a team from the European nuclear research facility (CERN) in Geneva, Switzerland, in 2012.
"How do I feel? Well, obviously I'm delighted and rather relieved in a sense that it's all over. It's been a long time coming," he said.
An old friend told him he had been nominated as far back as 1980, he explained.