Organization for Security and Cooperation in Europe (OSCE), formerly known as the Conference on Security and Cooperation in Europe (CSCE), multinational forum for the promotion of peace, security, justice, and cooperation in Europe. The CSCE formally convened in Helsinki, Finland, on July 3, 1973, after five years of discussion, preparation, and an easing of tensions (called détente) between the United States and the Union of Soviet Socialist Republics (USSR). The conference was attended by representatives of every European country except Albania, and by the United States, Canada, and the USSR.

The “Final Act” of the CSCE was signed on August 1, 1975, at a summit conference in Helsinki. The document, also known as the Helsinki Accords, provided for recognition of the existing frontiers between states, including the border that divided Germany into two sovereign states. In return for this provision, which was an implicit acknowledgment of Soviet domination in Eastern Europe, the USSR agreed to another mandate in which the signers pledged to respect basic human rights, including “freedom of thought, conscience, religion, and belief”; to ease travel restrictions; and to allow freer dissemination of information. Follow-up sessions to assess compliance were also part of the document and took place in the late 1970s and early 1980s.

By 1990 the collapse of most Communist regimes in Eastern Europe had carved out a new role for the CSCE. Meeting in November, the leaders of 34 nations (among them the newly unified Germany) signed the Charter of Paris for a New Europe, which recognized the end of the Cold War division of Europe and formed the CSCE's first permanent organs: a secretariat in Prague, Czechoslovakia (now the Czech Republic); a conflict-resolution center in Vienna, Austria; and an election-monitoring office in Warsaw, Poland. Estonia, Latvia, and Lithuania joined the CSCE in September 1991; 11 more former Soviet republics, plus Croatia and Slovenia, joined in early 1992, and Russia took the seat formerly held by the USSR. Subsequently, the CSCE admitted Bosnia and Herzegovina and suspended the former Yugoslavia. When Czechoslovakia broke up at the end of 1992, both the Czech Republic and Slovakia were admitted, raising the total active membership to 53.

In 1994 the organization changed its first name from the Conference on Security and Cooperation in Europe to the Organization for Security and Cooperation in Europe. The name was changed to mark a new period for the OSCE. The OSCE hoped to take a more active role in Europe, not only discussing problems, but also organizing missions and helping to resolve violence throughout Europe.