Treaty on the prohibition of nuclear weapons

Treaty overview

By resolution 71/258, the General Assembly decided to convene in 2017 a United Nations conference to negotiate a legally binding instrument to prohibit nuclear weapons, leading towards their total elimination. The Assembly encouraged all Member States to participate in the Conference, with the participation and contribution of international organizations and civil society representatives.

The Conference took place from 27 to 31 March and from 15 June to 7 July in New York.

The Treaty on the Prohibition of Nuclear Weapons (TPNW) includes a comprehensive set of prohibitions on participating in any nuclear weapon activities. These include undertakings not to develop, test, produce, acquire, possess, stockpile, use or threaten to use nuclear weapons. The Treaty also prohibits the deployment of nuclear weapons on national territory and the provision of assistance to any State in the conduct of prohibited activities. States parties will be obliged to prevent and suppress any activity prohibited under the TPNW undertaken by persons or on territory under its jurisdiction or control. The Treaty also obliges States parties to provide adequate assistance to individuals affected by the use or testing of nuclear weapons, as well as to take necessary and appropriate measure of environmental remediation in areas under its jurisdiction or control contaminated as a result of activities related to the testing or use of nuclear weapons.

The Treaty on the Prohibition of Nuclear Weapons was adopted by the Conference (by a vote of 122 States in favour, with one vote against and one abstention) at the United Nations on 7 July 2017, and opened for signature on 20 September 2017. Following the deposit with the Secretary-General of the 50th instrument of ratification or accession of the Treaty on 24 October 2020, it entered into force on 22 January 2021 in accordance with its article 15 (1).

Treaty implementation

Meetings of States Parties

Article 8(2) of the Treaty specifies that “the first meeting of States Parties shall be convened by the Secretary- General of the United Nations within one year of the entry into force of this Treaty. Further meetings of States Parties shall be convened by the Secretary-General of the United Nations on a biennial basis, unless otherwise agreed by the States Parties.”

The first Meeting of States Parties was held in Vienna, Austria, from 21 to 23 June 2022. The Meeting adopted a Declaration entitled “Our commitment to a world free of nuclear weapons” as well as the Vienna Action Plan for further implementation of the Treaty. The Meeting also took a number of additional decisions, including notably the establishment of deadlines for the removal from operational status and destruction of nuclear weapons and other nuclear explosive devices, and their removal from national territories, as required by article 4 of the Treaty. The report of the first Meeting (TPNW/MSP/2022/6) contains a record of all decisions taken at the Meeting.

The second Meeting of States Parties will take place at United Nations Headquarters in New York from 27 November to 1 December 2023. Further information can be found on Meetings Place.

Scientific Advisory Group

By its decision 2, the first Meeting of States Parties established a Scientific Advisory Group to be composed of a maximum of 15 members. The Group has a broad mandate to inform States Parties about developments in scientific and technical fields relevant to the Treaty, including the implementation of article 4 of the treaty, humanitarian consequences and risks associated with nuclear weapons and nuclear disarmament and non-proliferation more widely.

The Members of the Group were appointed on 8 February 2023 and held their constitutive meeting on 1 March 2023. More information about the work of the Scientific Advisory Group can be found on Meetings Place.

Role of the United Nations

By its resolution 72/31 of 4 December 2017, the General Assembly requested the Secretary-General to render the necessary assistance and to provide such services as may be necessary to fulfil the tasks entrusted to him under the Treaty on the Prohibition of Nuclear Weapons. Under Article 19, the Secretary-General is designated as depository of the Treaty. He is also tasked with the transmission to the States Parties of declarations received pursuant to Article 2 of the Treaty and the convening of Meetings of States Parties and Review Conferences (Article 8).


The initiative to seek a legally binding instrument to prohibit nuclear weapons is an outcome of the discourse centred on promoting greater awareness and understanding of the humanitarian consequences that would result from any use of nuclear weapons.

Renewed interest in the humanitarian impact of nuclear weapons was first manifested in the final document (NPT/CONF.2010/50 (Vol. I)) of the 2010 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons. In its conclusions and recommendations for follow-on actions, the Conference expressed its deep concern at the catastrophic humanitarian consequences of any use of nuclear weapons and reaffirmed the need for all States at all times to comply with applicable international law, including international humanitarian law.

In 2012, expressing concern about the catastrophic humanitarian consequences of any use of nuclear weapons, the General Assembly adopted resolution 67/56 entitled “Taking forward multilateral nuclear disarmament negotiations”. By this resolution, the Assembly established in 2013 an open-ended working group to develop proposals to take forward multilateral nuclear disarmament negotiations for the achievement and maintenance of a world without nuclear weapons and the open-ended working group reflected its discussion in its report (A/68/514).

A series of three international conferences on the humanitarian impact of nuclear weapons, convened in 2013 and 2014 respectively in Norway, Mexico and Austria, sought to present a facts-based understanding of the short and longer-term effects of a nuclear weapon detonation.

These conferences, which included participation by a large majority of States, the International Committee of the Red Cross and hundreds of representatives of non-governmental organizations, principally coordinated by the International Campaign to Abolish Nuclear Weapons (ICAN), played an important role in building demand for urgent action to advance nuclear disarmament negotiations.

General Assembly Resolutions:

Taking forward nuclear disarmament negotiations

Treaty on the Prohibition of Nuclear Weapons

Reports of the Open-ended working group taking forward multilateral nuclear disarmament negotiations

  • A/71/371 (2016) “Taking forward multilateral nuclear disarmament negotiations”
  • A/68/514 (2013) “Proposals to take forward multilateral nuclear disarmament negotiations for the achievement and maintenance of a world without nuclear weapons”

Reports of the Secretary-General