The International Atomic Energy Agency (IAEA) and its Director General Mohamed ElBaradei have received the Nobel Peace Prize in Oslo.
Mohamed ElBaradei will use his prize money to support orphans
They were being recognised for their efforts to contain the spread of nuclear weapons.
The award comes as the agency and its head are wrestling with the issue of Iran's nuclear ambitions.
Mr ElBaradei told the BBC Iran should be given another three months to co-operate fully with the agency.
He said UN sanctions may not persuade Tehran to end its nuclear programme.
"It might be slow, it might be frustrating, but diplomacy and verification is the way to go," he said.
"If we reach a dead end, if we discovered for example that Iran is not co-operating, is digging their heels, that we see a imminent threat, well we have a different ball game."
The prize consists of a Nobel diploma, a gold medal and 10 million Swedish kronor ($1.3m, £700,000), to be split between the agency and its head.
Mr ElBaradei has said his prize money will help support orphanages in his home country of Egypt.
"The award provides the agency with the added credibility, the moral authority and the visibility that we have today to speak on these issues," Mr ElBaradei told reporters in Oslo before the ceremony.
The chairman of the IAEA board of governors, Yukiya Amano, added: "Unfortunately nuclear weapons continue to exist and it has become likely that they [will] spread. Therefore, we need to work harder to prevent proliferation."
The award is made in honour of the IAEA's non-proliferation efforts in this 60th anniversary year of the 1945 bombings of Nagasaki and Hiroshima in Japan, the world's only combat use of atomic weapons.
The IAEA said anxiety about the danger posed by nuclear weapons was growing.
When the prize was announced, the Nobel committee said the IAEA's role was of "incalculable importance" at a time when the nuclear threat was growing.
While the Nobel Peace Prize ceremony is held at Oslo city hall, the Nobel awards for literature, medicine, physics, chemistry and economics will be presented in Stockholm.