1944 Dumbarton Oaks Conference, prelude to the United Nations, begins.
1945 Fifty nations gather in San Francisco, California to begin the United Nations Conference on International Organizations.
1945 Founding of the United Nations
1945 The official North Korean newspaper, Rodong Sinmun, is first published under the name ''Chongro''. Australia joins the United Nations.
1945 Colombia joins the United Nations.
1945 Venezuela joins the United Nations.
1945 By a vote of 65 to 7, the United States Senate approves United States participation in the United Nations (the UN was established on October 24, 1945).
1946 The first General Assembly of the United Nations opens in London. Fifty-one nations are represented.
1946 The last meeting of the League of Nations, the precursor of the United Nations, is held.
1946 Afghanistan, Iceland and Sweden join the United Nations.
1946 Thailand joins the United Nations.
1947 The Islamic Republic of Pakistan and Yemen join the United Nations.
1948 The World Health Organization is established by the United Nations.
1948 Burma (now Myanmar) joins the United Nations.
1948 Creation of the United Nations Peacekeeping Force the United Nations Truce Supervision Organisation
1948 Groundbreaking for the United Nations headquarters in New York City.
1949 United Nations cease-fire takes effect in Kashmir from one minute before midnight. War between India and Pakistan stops accordingly.
1949 Israel joins the United Nations.
1950 Edith Sampson becomes the first black U.S. delegate to the United Nations.
1950 United Nations troops recapture Seoul from the North Koreans.
1950 Indonesia is admitted to the United Nations.
1950 Indonesia joins the United Nations.
1950 Korean War: After the Chinese leadership finally settled the issue of armed intervention on October 18, the People's Republic of China joins the Korean War by sending thousands of troops across the Yalu river to fight United Nations forces.
1950 Korean War: Troops from the People's Republic of China launch a massive counterattack in North Korea against South Korean and United Nations forces (the Battle of the Ch'ongch'on River and the Battle of Chosin Reservoir), ending any hopes of a quick end to the conflict.
1950 Korean War: North Korean and Chinese troops force United Nations forces to retreat from North Korea.
1951 Korean War: For the second time, United Nations troops recapture Seoul.
1952 United Nations gives Eritrea to Ethiopia.
1952 Korean War: United Nations and South Korean forces launched Operation Showdown against Chinese strongholds at the Iron Triangle. The resulting Battle of Triangle Hill was the biggest and bloodiest battle of 1952.
1955 Albania, Austria, Bulgaria, Cambodia, Finland, Hungary, Ireland, Italy, Jordan, Laos, Libya, Nepal, Portugal, Romania, Spain and Sri Lanka join the United Nations.
1956 Morocco, Sudan and Tunisia join the United Nations.
1956 Japan joins the United Nations.
1957 Ghana joins the United Nations.
1957 Malaysia joins the United Nations.
1958 Guinea joins the United Nations.
1960 Mali and Senegal join the United Nations.
1960 Nigeria joins the United Nations.
1960 Cold War: Nikita Khrushchev pounds his shoe on a desk at United Nations General Assembly meeting to protest a Philippine assertion of Soviet Union colonial policy being conducted in Eastern Europe
1961 Sierra Leone joins the United Nations.
1961 The United Republic of Tanzania joins the United Nations.
1962 Algeria joins the United Nations.
1962 Uganda joins the United Nations.
1963 Kuwait joins the United Nations.
1964 Malawi, Malta and Zambia join the United Nations.
1965 Gambia, Maldives and Singapore are admitted as members of the United Nations.
1965 The Indo-Pakistani War of 1965 (also known as the Second Kashmir War) between India and Pakistan over Kashmir, ends after the UN calls for a cease-fire.
1965 Catholic Worker member Roger Allen LaPorte, protesting against the Vietnam War, sets himself on fire in front of the United Nations building.
1966 Botswana and Lesotho join the United Nations.
1966 Barbados joins the United Nations.
1968 Mauritius becomes a member state of the United Nations.
1968 Swaziland joins the United Nations.
1968 Equatorial Guinea joins the United Nations.
1970 Fiji joins the United Nations.
1971 U.N. Secretary General U Thant signs United Nations proclamation of the vernal equinox as Earth Day.
1971 The Soviet Union says it will support the People's Republic of China's admission to the United Nations
1971 Bahrain, Bhutan and Qatar join the United Nations.
1971 The United Nations seated the People's Republic of China and expelled the Republic of China (see political status of Taiwan and China and the United Nations)
1971 Representatives of the People's Republic of China attend the United Nations, including the United Nations Security Council, for the first time.
1971 The United Arab Emirates join the United Nations.
1973 A United Nations sanctioned cease-fire officially ends the Yom Kippur War between Israel and Syria.
1974 Bangladesh, Grenada and Guinea-Bissau join the United Nations.
1975 The Cape Verde Islands, Mozambique, and Sao Tome and Principe join the United Nations.
1975 Papua New Guinea joins the United Nations.
1975 United Nations Resolution 3379: United Nations General Assembly approves a resolution equating Zionism with racism (the resolution is repealed in December 1991 by Resolution 4686).
1975 The Comoros joins the United Nations.
1975 Suriname joins the United Nations.
1976 Angola joins the United Nations.
1976 Samoa becomes a member of the United Nations.
1977 The Socialist Republic of Vietnam is admitted to the United Nations.
1977 Djibouti and Vietnam join the United Nations.
1978 The Solomon Islands join the United Nations.
1978 Dominica joins the United Nations.
1980 Zimbabwe joins the United Nations.
1980 Saint Vincent and the Grenadines join the United Nations.
1981 Vanuatu becomes a member of the United Nations.
1981 Antigua and Barbuda joins the United Nations.
1982 Peruvian Javier Pérez de Cuéllar becomes the first Latin American to hold the title of Secretary General of the United Nations.
1983 Saint Kitts and Nevis joins the United Nations.
1984 Brunei joins the United Nations.
1987 According to the United Nations, the world population crosses the 5,000,000,000 (5 billion) mark.
1988 In a United Nations ceremony in Geneva, Switzerland, the Soviet Union signs an agreement pledging to withdraw its troops from Afghanistan.
1990 Namibia becomes the 160th member of the United Nations and the 50th member of the Commonwealth of Nations.
1990 Liechtenstein becomes a member of the United Nations.
1991 The United Nations deadline for the withdrawal of Iraqi forces from occupied Kuwait expires, preparing the way for the start of Operation Desert Storm.
1991 Bicesse Accords in Angola lay out a transition to multi-party democracy under the supervision of the United Nations' UNAVEM II mission.
1991 Estonia, North Korea, South Korea, Latvia, Lithuania, the Marshall Islands and Micronesia join the United Nations.
1992 Armenia, Azerbaijan, Kazakhstan, Kyrgyzstan, Moldova, San Marino, Tajikistan, Turkmenistan and Uzbekistan join the United Nations.
1992 Bosnia and Herzegovina, Croatia and Slovenia join the United Nations.
1992 Georgia joins the United Nations.
1992 UN Security Council Resolution 794 is unanimously passed, approving a coalition of United Nations peacekeepers led by the United States to form UNITAF, with the task of establishing peace and ensuring that humanitarian aid is distributed in Somalia.
1993 Czech Republic and Slovakia join the United Nations.
1993 The Republic of Macedonia joins the United Nations.
1993 Eritreans vote overwhelmingly for independence from Ethiopia in a United Nations-monitored referendum.
1993 Eritrea and Monaco join the United Nations.
1993 Andorra joins the United Nations.
1994 Palau gains independence from the United Nations (trusteeship administered by the United States of America).
1994 Palau becomes a member of the United Nations.
1995 The Cenepa War between Peru and Ecuador ends on a cease-fire brokered by the UN.
1996 U.S. President Bill Clinton signs the Comprehensive Nuclear-Test-Ban Treaty at the United Nations.
1997 Ghanaian diplomat Kofi Annan is appointed Secretary General of the United Nations.
1998 The UN's International Criminal Tribunal for Rwanda finds Jean Paul Akayesu, the former mayor of a small town in Rwanda, guilty of nine counts of genocide.
1998 Iraq disarmament crisis begins: Iraq announces it would no longer cooperate with United Nations weapons inspectors.
1999 Kosovo War: Operation Joint Guardian begins when a NATO-led United Nations peacekeeping force (KFor) enters the province of Kosovo in Federal Republic of Yugoslavia.
1999 Kiribati, Nauru and Tonga join the United Nations.
1999 The United Nations establishes the International Day for the Elimination of Violence against Women to commemorate the murder of three Mirabal Sisters for resistance against the Rafael Trujillo dictatorship in Dominican Republic.
1999 Kiribati, Nauru and Tonga join the United Nations.
2000 A United Nations tribunal sentences five Bosnian Croats to up to 25 years for the 1993 killing of over 100 Muslims in a Bosnian village.
2000 Tuvalu joins the United Nations.
2000 Serbia joins the United Nations.
2002 The trial of former President of Federal Republic of Yugoslavia Slobodan Milošević begins at the United Nations war crimes tribunal in The Hague. He dies four years later before its conclusion.
2002 Citizens of Switzerland narrowly vote in favor of their country becoming a member of the United Nations.
2002 Switzerland, traditionally a neutral country, joins the United Nations.
2002 Timor-Leste (East Timor) joins the United Nations.
2002 Iraq disarmament crisis: United Nations weapons inspectors led by Hans Blix arrive in Iraq.
2003 A car-bomb attack on United Nations headquarters in Iraq kills the agency's top envoy Sergio Vieira de Mello and 21 other employees.
2003 The United Nations lifts sanctions against Libya after that country agreed to accept responsibility and recompense the families of victims in the 1988 bombing of Pan Am Flight 103.
2007 Two car bombs explode at the Constitutional Court building in Algiers and the United Nations office. An estimated 45 people are killed in the bombings.
2008 Former Macedonian Interior Minister Ljube Boškoski is acquitted of all charges by a United Nations Tribunal accusing him of war crimes.