The Pugwash Conferences on Science and World Affairs, an anti-nuclear and security issues study group he helped found and now chairs, shared the prestigious award.
The Polish-born Briton, 86, said he hoped his prize would send a message to scientists about their duty to mankind.
"I am overwhelmed at the news," Rotblat said. "I hope that it will help other scientists recognize their social responsibility."
The Nobel Prize committee said the $1 million award was given to Rotblat and the Pugwash Conferences "for their efforts to diminish the part played by nuclear arms in international politics and in the longer run to eliminate such arms."
And in a blast that rang uncomfortably clear in Paris, both the five-person prize committee and Rotblat said the award was a protest against France's resumption of nuclear tests in the South Pacific.
"The specific message to the French is a protest against the nuclear tests, as it is a protest against nuclear tests in general and nuclear armaments in general," committee Chairman Francis Sejersted said.
Rotblat also pointed to China, which unlike other declared nuclear powers has not committed itself to ending nuclear tests.
France, squirming with embarrassment, praised the award but avoided mention of the criticism it entailed.
Poland rejoiced in its famous son and Japan, with its dreadful history as the only country victim to a nuclear bomb, warmly applauded the committee's decision.
Takeshi Ito, of the federation of atomic bomb weapons survivor groups, fondly recalled Rotblat's tearful apology for his part in the development of weapons of mass destruction at a 1977 rally of the victims of the Nagasaki bombing.
Rotblat worked on the U.S. Manhattan Project to develop nuclear weapons during World War II but left the research group when it became clear that Germany had abandoned its plans to build the atom bomb.
"The whole idea of us making the bomb was that it not be used," he said. When the United States dropped the first bomb on Hiroshima he was devastated. For walking out on the Manhattan project he was barred from the U.S. for nearly 20 years.
He dedicated his life to fighting the nuclear arms race. In 1955 he signed an anti-war manifesto drafted by British philosopher Bertrand Russell and endorsed by Albert Einstein.
That document proved a rallying cry for action at the height of the Cold War and paved the way for the first meeting of scientists, politicians and thinkers in the remote village of Pugwash in Canada's Nova Scotia province in 1957.
The 45th invitation-only meeting was held in Hiroshima last year on the 50th anniversary of the dropping of the first bomb.
The Pugwash movement has been credited with an important behind the scenes role in keeping open lines of communication between the Soviet Union and the United States when relations between the two superpowers were glacial.
Rotblat and Pugwash have also won plaudits for quietly and thoroughly promoting the cause of nuclear disarmament
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