The United States has promised to rejoin the United Nations Educational, Scientific and Cultural Organization (UNESCO), nearly two decades after it severed ties with the organization.

President George W. Bush made the announcement during a speech to the UN General Assembly in New York on 12 September, saying that the organization had been sufficiently reformed. The United States withdrew its funding and staff in 1984 on the grounds that UNESCO had become too bureaucratic and politicized.

UNESCO, which was founded after the Second World War to promote international collaboration on scientific and cultural issues, has a relatively small science budget of about US$50 million. It runs several influential international science bodies, such as the Intergovernmental Oceanographic Commission, which helps to coordinate ocean research.

The decision was welcomed by US scientists who had urged their country to rejoin the organization.

“It seemed rather anomalous that a great country like this wouldn't support it,” says James Cronin, a physicist at the University of Chicago and a member of the Pierre Auger Observatory, a cosmic-ray detector currently under construction in Argentina (see Nature 419, 12–14; 2002) that UNESCO has helped to fund. Cronin was also one of 37 Nobel laureates who unsuccessfully petitioned President Bill Clinton to rejoin the organization in 1993.

The impact of the decision remains unclear, however. UNESCO's budget will not immediately increase, as the United States' contribution of $60 million a year will be subtracted from the total payments made by other countries. But the move could allow US researchers to push for the organization to divert more of its resources to scientific projects.

“The 'S' stands for science, but it's the smallest 'S' you can imagine,” says Cronin.