SÚrgio Vieira de Mello (March 15, 1948 - August 19, 2003) was a Brazilian diplomat who worked for the United Nations (UN) for over 30 years, earning respect and praise around the world for his efforts in the sometimes amorphous humanitarian programs of the UN. Born in Rio de Janeiro, Vieira de Mello studied philosophy at the Sorbonne University in Paris before embarking on a career in the UN when he was 21. Suave, polished and attractive, he was fluent in English and French, as well as his native Portuguese.

He joined the U.N. High Commission for Refugees in 1969, serving in Bangladesh during its independence in 1971. Following the 1974 Turkish invasion of Cyprus he worked with refugees. He spent three years in charge of UNHCR operations in Mozambique during the civil war that followed its independence from Portugal in 1975, and three more in Peru. He became senior political adviser to the U.N. Interim Force in Lebanon between 1981 and 1983. Vieira de Mello then returned to the UNHCR, working at its head office in Geneva for a decade. The early 1990s found him in involved in the clearing of land mines in Cambodia, and then in Yugoslavia. After working on the refugee problem in central Africa, he was made Assistant High Commissioner for Refugees in 1996 and he became UN Undersecretary-General two years later. He was a special UN envoy in Kosovo after the end of Serbian control of the former Yugoslav province in 1999. Vieira de Mello was instrumental in dealing with the issue of boat people in Hong Kong.

Before becoming the UN High Commissioner for Human Rights in 2002, he was the UN Transitional Administrator in East Timor from December 1999 to May 2002, guiding that former Portuguese colony occupied by Indonesia to independence. He was also special representative in Kosovo for an initial period of two months and was the coordinator of humanitarian operations at UN headquarters.

In May 2003 Vieira de Mello was appointed as the UN Special Representative in Iraq, an appointment initially intended to last for four months. He had been working in this position when he was killed in the Canal Hotel bombing on the afternoon of August 19, 2003.

He was mentioned in some circles as a suitable candidate for UN Secretary General. His death was mourned in Brazil (where three days of official mourning were declared), East Timor, Portugal (because of his work in Timor) and Cambodia among many other places, where his actions had brought him a reputation for extreme efficiency, liveliness and love of peace.

Vieira de Mello was married but separated from his wife, and is survived by two sons. He was buried at Geneva's Cimetiere des Rois (Cemetery of Kings).