Sérgio de Queiroz Duarte is a former Brazilian diplomat who served as Ambassador to Nicaragua, Canada, China and Austria, concurrently accreditated as Ambassador to Slovenia, Slovakia and Croatia and United Nations organisations in Vienna. His last position was as United Nations High Representative for Disarmament Affairs, appointed by UN Secretary-General Ban Ki-moon in July 2007 and retired in February 2012.
Previously, Duarte was the President of the 2005 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons. From 2003 to 2004, he served as Brazil’s Roving Ambassador for Disarmament Affairs. Between 1999 and 2002, he was his country’s Permanent Representative to the UN at Vienna and Chairman of the International Atomic Energy Agency Board of Governors. From 1979 to 1986, he served as Alternate Representative of Brazil in the Office of the Special Representative of Brazil for Disarmament Affairs in Geneva. He was also posted to the Permanent Mission to the United Nations in Geneva from 1966 to 1968.