On July 1, 1968, the Treaty on the Nonproliferation of Nuclear Weapons was opened for signature in three Depository state capitals: Washington, London, and Moscow. This year we mark the 50th anniversary of the NPT’s entry into force. The United States celebrates this important milestone and applauds the immeasurable contribution this landmark treaty has made to international security. The NPT has provided the essential foundation for international efforts to stem the looming threat – then and now – that nuclear weapons would spread across the planet.

The maintenance of a strong nonproliferation regime grounded in the NPT helped create a secure and stable security environment conducive to progress in nuclear disarmament. The NPT facilitates cooperation on peaceful uses of nuclear energy that delivers a broad spectrum of services and products that, for example, diagnose and fight diseases, develop new crops, manage scarce water resources, and broadly apply nuclear science and technology to help meet the UN Sustainable Development Goals.

In honor of the 50th anniversary of the Treaty on the Non-Proliferation of Nuclear Weapons, and to mark the occasion, we embarked on a historical access project to make formerly classified documents relating to NPT history available to the public for the first time.

On March 5, 2020, fifty years after the treaty entered into force, the State Department released scores of documents from the records of the Arms Control and Disarmament Agency (ACDA) covering the negotiation, signature, and ratification of the NPT. These documents are posted here.

On June 28, 2018, we released key documents relating to the history of the negotiation of the NPT, compiled by ACDA, along with the histories for other treaties negotiated in in the Eighteen-Nation Disarmament Committee. We also released declassified scenario documents and background memos for the NPT’s signing in Washington on July 1, 1968. These documents are posted here.

Additional documents related to the negotiation of the NPT can be found under Foreign Relations of the United States and at the Department’s FOIA web page.

Further resources on the origins of the NPT are available at the Lyndon B. Johnson Library the National Archives , and the Woodrow Wilson Center. The United Kingdom and NATO have also released their own collections of documents on their respective roles in support of NPT negotiations.

Historical Documents and Photos

U.S. Department of State

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