The United Nations is the most comprehensive organization in the world. UN was established after the end of World war II on October 24, 1945 and its charter was signed by 51 countries in San Fransisco, USA. The name United Nations was coined by Franklin D. Roosevelt. UN now has 193 member countries. UN uses English, French, Chinese, Spanish, Russian and Arabic as its official language. United Nations operations are carried out by six major bodies viz., (i) United nations Security Council (UNSC) (ii) United nations General Assembly (UNGA) (iii) United nations economic and social council (ECOSOC) (iv) United Nations Trusteeship council (UNTC) (v) International Court of Justice (ICJ) (vi) Secretariat. United nations has various specialized bodies through which it works on various social, political and other issues. Specialized Agencies are legally independent international organizations with their own rules, membership, organs and financial resources, were brought into relationship with the United Nations through negotiated agreements. Some of the agencies existed before the First World War, some were associated with the League of Nations, others were created almost simultaneously with the United Nations and yet others were created by the United Nations itself to meet emerging needs. Given the diversity of their respective fields of action, history and experience, each agency has its own needs and concerns, not to speak of corporate culture.

UN Organization Acronym Estd. Nepal joined Remarks
Prepatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization CTBTO 1996
United Nations Economic Commission for Latin America and the Caribbean ECLAC 1948
United Nations Economic and Social Commission for Asia and the Pacific ESCAP 1947
United Nations Economic and Social Commission for Western Asia ESCWA 1973
Food and Agriculture Organization FAO 1945 1951
International Atomic Energy Agency IAEA 1957
International Bank for Reconstruction and Development IBRD 1945 World bank group
International Civil Aviation Organization ICAO 1947
International Civil Service Commission ICSC 1975
International Centre for Settlement of Investment Disputes ICSID 1965 World bank group
International Development Association IDA 1960 World bank group
International Fund for Agricultural Development IFAD 1977 1978
International Finance Corporation IFC 1956 World bank group
International Labour Organization ILO 1919 1966
International Monetary Fund IMF 1945
International Maritime Organization IMO 1948 2006
International Trade Centre ITC 1964
International Telecommunication Union ITU 1865
Joint Inspection Unit JIU 1976
Multilateral Investment Guarantee Agency MIGA 1988 World bank group
Office of the United Nations High Commissioner for Human Rights OHCHR 1993
Organization for the Prohibition of Chemical Weapons OPCW 1997
UN Women UN Women 2010
Joint United Nations Programme on HIV/AIDS UNAIDS 1994
United Nations Conference on Trade and Development UNCTAD 1964
United Nations Development Programme UNDP 1965
United Nations Economic Commission for Africa UNECA 1958
United Nations Economic Commission for Europe UNECE 1947
United Nations Environment Programme UNEP 1972
United Nations Educational, Scientific and Cultural Organization UNESCO 1945 1953
United Nations Framework Convention on Climate Change UNFCCC 1992
United Nations Population Fund UNFPA 1969 1971
United Nations Human Settlements Programme UN-Habitat 1978
Office of the United Nations High Commissioner for Refugees UNHCR 1950
United Nations Children’s Fund UNICEF 1946 1964
United Nations Interregional Crime and Justice Research Institute UNICRI 1969
United Nations Institute for Disarmament Research UNIDIR 1980
United Nations Industrial Development Organization UNIDO 1966
United Nations International Strategy for Disaster Reduction UNISDR 1999
United Nations Institute for Training and Research UNITAR 1963
United Nations Office on Drugs and Crime UNODC 1997
United Nations Office for Project Services UNOPS 1973
United Nations Research Institute for Social Development UNRISD 1963
United Nations Relief and Works Agency for Palestine Refugees in the Near East UNRWA 1949
United Nations System Staff College UNSSC 2002
United Nations University UNU 1973
World Tourism Organization UNWTO 1957
Universal Postal Union UPU 1874
World Food Programme WFP 1961
World Health Organization WHO 1948
World Intellectual Property Organization WIPO 1967
World Meteorological Organization WMO 1950
World Bank Group World Bank 1945
World Trade Organization WTO 1995