The Argentine Republic is a founding member of the United Nations and has since played an active role in the defense and promotion of International Peace and Security, Human Rights and Sustainable Development.
In 1945, representatives of 50 countries including the Argentine Republic met in San Francisco at the United Nations Conference on International Organization to draw up the United Nations Charter.
The Charter was signed on June 26, 1945 by the representatives of the 50 countries. The United Nations officially came into existence on October 24, 1945 when the Charter had been ratified by a majority of signatory states.
United Nations Day is celebrated every year on that date.
More information on the history of the United Nations can be found at the following link:
http://www.un.org/en/sections/history/history-united-nations/index.html