The United Nations has 193 member states.
The organization began in 1945 with 51 members, created after the Second World War to encourage international cooperation and help prevent future conflicts. Membership expanded as colonies became independent and newly sovereign countries joined the international system. The latest country admitted was South Sudan, which became the 193rd member on 14 July 2011.
The number 193 refers to full member states, not every entity represented at the United Nations. The Holy See and the State of Palestine hold non-member observer-state status. Some territories and partially recognized governments also participate in international affairs without being UN members.
Each member state has a seat in the General Assembly, where all members can debate and vote on resolutions. The Security Council is different: it has 15 seats, including five permanent members with veto power. UN membership therefore does not mean every country has the same role in every organ.