Over time, the EU has grown from six countries to 27, absorbing countries in Eastern Europe as they emerged from decades under communist rule.
“Today war between Germany and France is unthinkable. This shows how, through well-aimed efforts and by building up mutual confidence, historical enemies can become close partners,” the committee said.
The citation also noted the democratic conditions the EU has demanded of all those nations waiting to join, referred to Greece Spain and Portugal when they joined in the 1980's after dictatorships, and to the countries in Eastern Europe who sought EU membership after the 1989 fall of the Berlin Wall.
“The EU is currently undergoing grave economic difficulties and considerable social unrest,” Jagland said. “The Norwegian Nobel Committee wishes to focus on what it sees as the EU's most important result: the successful struggle for peace and reconciliation and for democracy and human rights.
It was not yet clear who would accept the prize for the EU.
The EU has been seen as possible candidate for the Nobel for many years, and the members of the committee had previously praised the community's significance as a promoter of peace and democracy in Europe. The chairman, Jagland, is also the secretary-general of the Council of Europe, a human rights group.
But skepticism against the EU runs high in oil-rich Norway, which is not a member and where popular opinion is firmly against membership. Norwegian voters rejected joining the EU twice, in 1972 and 1994.
The EU's success in making war between Germany and France unthinkable is beyond dispute. On the contrary, those two countries tend now to be the EU's dominant players, with the French president and the German chancellor often getting together to, in effect, hash out EU policy.
Britain has always been a half-hearted member since joining in the 1970s, and is not part of the 17-nation eurozone that shares a common currency.
While there have never been wars inside EU territory, the confederation has not been able to prevent European wars outside its borders. When the deadly Balkans wars erupted in the 1990s, the EU was unable by itself to stop them. It was only with the help of the United States and after over 100,000 lives were lost in Bosnia was peace eventually restored there, and several years later, to Kosovo.
Ritter reported from Stockholm. AP reporter Louise Nordstrom in Stockholm and Don Melvin in Brussels contributed to this report.