Tlatelolco Treaty

Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (LANWFZ) (Tlatelolco Treaty)

The Tlatelolco Treaty prohibits Latin American states from acquiring, possessing, developing, testing or using nuclear weapons, and prohibits other countries from storing and deploying nuclear weapons on their territories.

  • Ratified

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Ratified (33)

  • Flag for Antigua and Barbuda Antigua and Barbuda
  • Flag for Argentina Argentina
  • Flag for Bahamas Bahamas
  • Flag for Barbados Barbados
  • Flag for Belize Belize
  • Flag for Bolivia Bolivia
  • Flag for Brazil Brazil
  • Flag for Chile Chile
  • Flag for Colombia Colombia
  • Flag for Costa Rica Costa Rica
  • Flag for Cuba Cuba
  • Flag for Dominica Dominica
  • Flag for Dominican Republic Dominican Republic
  • Flag for Ecuador Ecuador
  • Flag for El Salvador El Salvador
  • Flag for Grenada Grenada
  • Flag for Guatemala Guatemala
  • Flag for Guyana Guyana
  • Flag for Haiti Haiti
  • Flag for Honduras Honduras
  • Flag for Jamaica Jamaica
  • Flag for Mexico Mexico
  • Flag for Nicaragua Nicaragua
  • Flag for Panama Panama
  • Flag for Paraguay Paraguay
  • Flag for Peru Peru
  • Flag for Saint Kitts and Nevis Saint Kitts and Nevis
  • Flag for Saint Lucia Saint Lucia
  • Flag for Saint Vincent and the Grenadines Saint Vincent and the Grenadines
  • Flag for Suriname Suriname
  • Flag for Trinidad and Tobago Trinidad and Tobago
  • Flag for Uruguay Uruguay
  • Flag for Venezuela Venezuela

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Opened for Signature

14 February 1967

Entered into Force

25 April 1969



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Treaty Overview

On 23 October 2002, the Tlatelolco Treaty came into full force throughout the region when Cuba, the only state which had not ratified the treaty, deposited its instrument of ratification. Currently, all 33 states in the region of Latin America and the Caribbean have signed and ratified the treaty. The Tlatelolco Treaty has served as a model for all future nuclear-weapon-free zone (NWFZ) agreements.


Costa Rica was the first regional state to propose a Latin American nuclear arms control arrangement at an Organization for the American States (OAS) Council meeting in 1958, which sought to prevent the manufacture of nuclear arms or their acquisition from the nuclear weapon states (NWS). Other proposals were unsuccessfully floated within the OAS context during 1958-1960.

French nuclear weapon testing in the Sahara in 1960, together with the South African apartheid regime’s interest in nuclear arms, led the African states to issue a call for an African NWFZ, which was endorsed by the UN General Assembly in 1961. Alone among Latin American states, Brazil supported the African NWFZ resolution and proposed a similar zone within its region. The efforts of Alfonso Garcia Robles, as Mexican ambassador to Brazil, eventually led, in March 1963, to Bolivia, Brazil, Chile, and Ecuador joining Mexico in supporting a Latin American NWFZ.

Treaty Zone

The treaty covers the entire Latin American and Caribbean region and large sectors of the Pacific and Atlantic Oceans.

Treaty Obligations

The treaty aims to prohibit and prevent in the region: (a) the testing, use, manufacture, production, or acquisition by any means whatsoever of any nuclear weapons, by the Parties themselves, directly or indirectly, on behalf of anyone else, or in any other way, and (b) the receipt, storage, installation, deployment, and any form of possession of any nuclear weapons, directly or indirectly, by the Parties themselves, by anyone on their behalf, or in any other way. The Parties also undertake to refrain from engaging in encouraging or authorizing, directly or indirectly, or in any way participating in the testing, use, manufacture, production, possession, or control of any nuclear weapons.

Verification and Compliance


Verification is accomplished by concluding multilateral or bilateral agreements with the International Atomic Energy Agency (IAEA) for the application of its safeguards to nuclear activities of States Parties to the treaty. In addition, the Agency for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (OPANAL) is an inter-governmental agency created by the Treaty of Tlatelolco to ensure that the obligations of the treaty are met.


The General Conference, the supreme organ of the OPANAL agency, will take note of all cases in which any Contracting Party is not complying fully with its obligations under this treaty and shall draw the matter to the attention of the Party concerned, making such recommendations as it deems appropriate. If such non-compliance constitutes a violation of this treaty which might endanger peace and security, the General Conference may report simultaneously to the United Nations Security Council and the General Assembly through the Secretary-General of the United Nations, and to the Council of the Organization of American States. The General Conference shall likewise report to the IAEA for such purposes as are relevant in accordance with its Statute.

Additional Protocol I provides for the application of the status of denuclearization in territories for which, de jure or de facto, France, the Netherlands, the United Kingdom, and the United States are internationally responsible, and which lie within the limits of the geographic zone established by the treaty. All four states have acceded to Protocol I. Signed: France on 2 March 1979, the Netherlands on 15 March 1968, United Kingdom on 20 December 1967, and United States on 26 May 1977. Ratified: France on 24 August 1992, the Netherlands on 26 July 1971, United Kingdom on 11 December 1969, and United States on 23 November 1981.

Additional Protocol II obliges all NWS officially recognized by the international community to respect the status of denuclearization of the relevant geographic zone and commits them not to use or threaten to use nuclear weapons against parties to the treaty. All five NWS acceded to the protocol. Ratified: France on 22 March 1974, China on 2 June 1974, United Kingdom on 11 December 1969, United States on 12 May 1971, and USSR on 8 January 1979.

Point of Contact

Agency for the Prohibition of Nuclear Weapons in
Latin America and the Caribbean (OPANAL)

Col. Chapultepec Morales
Schiller 326 – 5º piso
México D.F. 11570 México
Phone: (52-55) 5255-2914, 5255-4198 and 5545-9251
Fax: (52-55) 5255-3748




From 23 April to 4 May, OPANAL participated as an Observer International Organization in the second Preparatory Committee for the 2020 NPT Review Conference. Ambassador Soares, OPANAL’s Secretary-General, delivered a statement in the general debate highlighting the benefits of NWFZs and reminding delegates of Action 9 of the 2010 Action Plan, which encouraged the establishment of NWFZs.

On 20 September, the 316th Meeting of the Council of OPANAL was held at OPANAL headquarters. Ambassador Jorge Alberto Delgado Fernandez, Permanent Representative of Uruguay to OPANAL, chaired the meeting.

On 21 September, OPANAL participated in the IAEA’s 62nd General Conference. Ambassador Eric Anderson Machado, Coordinator of OPANAL in Vienna and Permanent Representative of Peru to the IAEA, delivered a statement affirming NWFZs and highlighting OPANAL’s status as the only international organization attached to a NWFZ treaty.

On 17 October, Ambassador Luiz Filipe de Macedo Soares, the Secretary-General of OPANAL participated in the First Committee of the UNGA and a panel on the “Current State of Affairs in the Field of Arms Control and Disarmament.” The Secretary-General offered comments during the panel highlighting optimism over diplomatic talks regarding the Korean Peninsula, and the importance of NWFZs.

On 15 November, the XXVI Special Session of the General Conference of OPANAL was held at Argentinian embassy in Mexico City, Mexico. The General Conference adopted resolutions pursuant to internal OPANAL matters and addressed heightened international tensions in its general debate.

On 5 December, the UN General Assembly adopted resolution 73/71, calling for the convening of a fourth Conference of Nuclear Weapons Free Zones and Mongolia at UN Headquarters on 24 April 2020. The resolution also encouraged talks toward the establishment of a Middle East Nuclear Weapons Free Zone.


On 14 February, the Treaty of Tlatelolco celebrated its 50th anniversary.

On 23 March, OPANAL submit a working paper entitled “Recommendations for the negotiation of a legally binding instrument to prohibit nuclear weapons, leading towards their total elimination,” to the UN General Assembly.

On 4 May, Ambassador Luiz Filipe de Macedo Soares, the Secretary General of OPANAL, delivered a statement at the First Session of the Preparatory Committee for the 2020 Review Conference of the Parties to the Treaty on the Nonproliferation of Nuclear Weapons. The Secretary General emphasized the importance of nuclear-weapon-free zones.


On 5 February, OPANAL held a special session due to the visit of Mr. Yukiya Amano, Director General of the IAEA. Mr. Amano reported that all members of OPANAL have completed their comprehensive safeguards and stated “the Treaty of Tlatelolco is a very good example to other countries.”

On 14 February, the Treaty of Tlatelolco and OPANAL celebrated its 49th anniversary.

On 5 April, South Korea and Mexico resumed discussions on trade between the two nations. Part of these discussions included a promise from Mexico to share their experience negotiating the Treaty of Tlatelolco allowing South Korea to apply this knowledge to negotiating a NWFZ.

On 11 October, the Secretary General of OPANAL delivered a statement at the First Committee of the UN General Assembly. The Secretary General emphasized the danger of nuclear weapons and the importance of a road towards the abolition of nuclear weapons.

On 10 November, OPANAL held the 24th Special Session of the General Conference in Mexico City.



On 23 February, OPANAL submitted a memorandum to the NPT Review Conference on their activities regarding the Treaty of Tlatelolco since the 2010 NPT Review Conference.

On 23 March, talks between the US and Cuba reaffirmed Latin America as a “Zone of Peace” based on the Treaty of Tlatelolco and international law.

On 27 April, Ecuador delivered a statement on behalf of CELAC at the General Debate of the 2015 NPT Review Conference. They emphasized their commitment in establishing a nuclear weapons free world, and underscored the importance of using the Treaty of Tlatelolco as a “political, legal, and institutional reference point” to foster future NWFZs. They further implored Nuclear-Weapons States to remove their interpretations on the Protocols to the Treaty.

On 30 April, Secretary-General Ambassador Luiz Filipe de Macedo Soares delivered the OPANAL statement to the 2015 NPT Review Conference. He specifically noted the political difficulty of establishing a Nuclear-Weapons-Free Zone in the Middle East by contrasting it with the geopolitical situation surrounding the Treaty of Tlatelolco in the 1960s.

On 12 October, Ecuador issued a statement at the 2015 UN General Assembly General Debate. Speaking on behalf of CELAC, Ecuador reaffirmed their supportive stance towards Nuclear-Weapons-Free Zones around the world, recalling the Treaty of Tlatelolco as the first such zone. Ecuador further urged the Nuclear Weapons States to “withdraw all interpretive declarations to the Protocols” to the Treaty and to respect Latin America as a Nuclear-Weapons-Free Zone.

On 21 November, OPANAL held the 24th session of the General Conference in Mexico City. One of the main topics of discussion was that of nuclear disarmament and nonproliferation education.


On 28-29 January, at the Second Summit of the Community of Latin American and Caribbean States in Havana, the Latin America and the Caribbean was declared a “Zone of Peace” based on the Treaty of Tlatelolco and international law. Member states reaffirmed their commitment to abide by the treaty’s nuclear disarmament policy.

On 14 February, the Tlatelolco treaty celebrated its 47th anniversary.

On 20 March, Ambassador Luiz Filipe de Macedo Soares, Secretary-General of the Agency for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (OPANAL), presented a statement to the Committee on Hemispheric Security of the Permanent Council of the Organization of American States. The statement described progress taken in light of Resolution AG/RES. 2624 (XLI-0/11) “Consolidation of the Regime established in the Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (Treaty of Tlatelolco).” The Secretary-General discussed member states’ compliance with the treaty and, while admitting there are still challenges to be faced, deemed the treaty “a gift from Latin America and the Caribbean to the world.”


On 17 January, OPANAL Secretary-General Ambassador Gioconda Ubeda, presented a progress report on relevant developments of the consolidation process of the Nuclear-Weapon-Free Zone in Latin America and the Caribbean (NWFZ), at the request of the Committee on Hemispheric Security (CHS) of the Organization of American States (OAS). Highlighting the contribution of the Treaty of Tlatelolco to global nuclear disarmament and non-proliferation, Ubeda emphasized that OPANAL is building a consensual political agenda that highlights, inter alia, Nuclear Disarmament and Non-Proliferation Education, the strengthening of the Control System that guarantees military denuclearization of the NWFZ, and actions aimed at reaching a world free of nuclear weapons.

On 7 February, 33 heads of State of CELAC (also party to the Tlatelolco Treaty) pushed for disarmament and pledged to continue their commitment to a nuclear weapons-free world at the High Level Meeting of the United Nations General Assembly on Nuclear Disarmament on 26 September 2013 in New York.

On 13 February, UN Secretary General Ban Ki-moon praised the region’s efforts to stop nuclear proliferation and stated that “the Treaty of Tlatelolco is a model for the world to follow.”

On 14 February, Tlatelolco celebrated its 46th Anniversary.

From 29 September to 1 October, the Director General of the IAEA visited Havana, Cuba. The DG praised the Tlatelolco Treaty and ongoing Technical Cooperation Programs between the IAEA and countries in the region.

On 23 October the Treaty of Tlatelolco was chosen out of 24 nominated policies as the winner of the 2013 Future Policy Award for “sustainable disarmament.” The award, presented by the World Future Council, the UN Office for Disarmament Affairs (UNODA) and the Inter-Parliamentary Union, commended the treaty’s importance to the creation of other Nuclear-Weapons-Free Zones and its role in “advancing regional peace and security.




On 14 February, the Treaty of Tlatelolco had its 45th Anniversary. United Nations Secretary-General Ban Ki-moon hailed the pact as an example of how regional initiatives can advance global norms on nuclear disarmament, non-proliferation and the peaceful use of atomic energy. IAEA Director General Yukiya Amano also acclaimed the achievement of the Treaty of Tlatelolco in providing inspiration for four similar treaties in Africa, Central Asia, Southeast Asia and the Pacific.

On 27 April, Ambassador Alfredo Labbé addressed the First Preparatory Meeting for the Third Conference of States Parties and Signatories to the Treaty Establishing Nuclear Weapon-Free Zones and Mongolia, on behalf of OPANAL Secretary-General Gioconda Ubeda, and stressed the need for joint leadership among the five NWFZs in order to strengthen coordination and cooperation among the NWFZs.

On 3 May, Secretary-General of OPANAL Gioconda Ubeda addressed the NPT PrepCom and expressed OPANAL’s hope that the five NWS would soon sign or ratify the Additional Protocols of all NWFZ treaties. Additionally, he offered to share the experience of the NWFZ in Latin America and the Caribbean at the 2012 Conference on the Establishment of a NWFZ in the Middle East.

On 15 October in New York, the Secretary General of OPANAL, Gioconda Ubeda, spoke at the 67th Session of the First Committee of the United Nations General Assembly. Ubeda addressed several topics, including Nuclear Disarmament and Nonproliferation Education, the contribution of nuclear-weapon-zones to disarmament and nonproliferation, the need for Annex II States parties to the CTBT to sign and ratify the CTBT, and the intrinsic relationship between OPANAL and the IAEA. In addition, Ubeda called attention to the seminar “The Experience of the NWFZ in Latin America and the Caribbean and the prospective towards 2015 and beyond,” which was held within the framework of the Commemorative Events on the Occasion of the 45th Anniversary of the signing of the Treaty of Tlatelolco.


On 16 June in Geneva, the Secretary General of OPANAL, Gioconda Ubeda, spoke at the first plenary meeting of the Conference on Disarmament. Ubeda addressed the importance of strengthening multilateral dialogue among nations, essential for establishing nuclear-weapon-free zones (NWFZ) around the world. In addition, she recognized that the 114 states that make up the five nuclear weapons free zones have much to contribute to the global community but still face a large task of helping eliminate the threat presented by nuclear weapons.


On 30 April, the Second Conference of States Parties and Signatories of Treaties that Establish Nuclear-Weapon-Free Zones and Mongolia was held in New York. The conference adopted the Outcome Document which reiterated the final declaration of the 2005 Conference and welcomed the entry into force of the African and Central Asian NWFZs as well as the efforts of Mongolia to institutionalize its nuclear weapons free status. It further called on the nuclear-weapons states to sign all relevant protocols and withdraw existing reservations.

On 31 October, the General Secretariat of OPANAL recommended that Article 18 of the Treaty of Tlatelolco, which permits peaceful nuclear explosions for the purpose of technological development, be studied and revised. In support of this recommendation, the General Secretariat memorandum observed that nuclear explosions had proven “unnecessary for the development of nuclear technology” and noted that the treaty’s 33 member states were opposed to nuclear testing of any kind.


On 17 April, the Council of OPANAL passed Resolution C/Res. 47, which notes with satisfaction the creation of a Nuclear-Weapon-Free-Zone in Central Asia and promotes cooperation with the new NWFZ in order to fulfill common objectives set forth by the Treaty of Tlatelolco and the Central Asian NWFZ Treaty.

From 27-28 April, a Meeting of Focal Points of Nuclear Weapon Free Zones and Mongolia was held in Ulaanbaatar, Mongolia. Both the importance of universalizing the NPT and the necessity for entry into force of the CTBT were reiterated, Preparations for the 2010 NPT Review Conference, and the Third PrepCom were also discussed. States parties to the Treaty of Tlatelolco submitted a working paper to the PrepCom.

On 26 November, the XXI Regular Session of the General Conference of OPANAL met in Mexico City and adopted one resolution related to the Tlatelolco Treaty: CG/Res.515 Interpretative Declarations of the Nuclear Powers to Protocols I and II of the Treaty of Tlatelolco.



On 8 February, the Organization of American States Permanent Council’s Committee on Hemispheric Security convened in special session to consider OAS progress with respect to initiatives on the CTBT and related instruments. The session received briefings from the OPANAL, CTBTO, and UNODA, and reaffirmed the OAS commitment to the Western Hemisphere as a nuclear weapons free-zone and stressed its support for the CTBT.

On 14 February, OPANAL organized a seminar on the “Treaty of Tlatelolco” for the occasion of the 41st anniversary of the opening for signature of the Treaty of Tlatelolco.


On 14 February, members of the Treaty of Tlatelolco met in Mexico City to celebrate the Treaty’s 40th anniversary.

On 28 June, OPANAL adopted resolution C/Res.43 on procedural issues relating to the resignation of Secretary General Edmundo Vargas Carreno. The OPANAL council resolved to assume the duties of the Secretary General until a new one is elected.


On 11 September, OPANAL adopted resolution C/Res.41. The resolution welcomed the establishment of the Central Asian Nuclear-Weapons Free Zone and instructed the Secretary General to congratulate the relevant republics on its behalf.

On 7 December, OPANAL adopted resolution C/Res.42 on strengthening the organization. The resolution urges OPANAL members to promote campaigns to disseminate the principles and objectives of the Treaty.


On 26-28 April, the Conference of States Parties and Signatories of Treaties that establish Nuclear-Weapon-Free Zones was held in Tlatelolco, Mexico. The Conference adopted a declaration, reaffirming that nuclear weapons constitute a threat to humanity, urging nuclear weapons states to adopt negative security assurances, and stressing the importance of the right to peaceful uses of nuclear energy.


The XVIII Session of the General Conference of OPANAL adopted several resolutions related to the Tlatelolco Treaty: CG/Res. 439 Status of the Treaty and its Additional Protocols, CG/Res. 444 Prevention of Radioactive Contamination of the Marine Environment within the Framework of the Treaty of Tlatelolco: Transportation of radioactive material, and CG/Res. 447 Declarations of Nuclear Powers to the Additional Protocols I and II of the Treaty of Tlatelolco.


On 23 October, Cuba ratified the Tlatelolco Treaty. With its ratification, the treaty came into full force throughout all 33 states within the region. Cuba had announced to the UNGA that it would accede to the NPT and ratify the Tlatelolco Treaty on 14 October.



On 25 March, Cuba signed the Tlatelolco Treaty and subsequently signed its amendments in December. However, Cuba did not ratify the treaty. By this point in time, all 33 states in Latin America and the Caribbean had become signatories of the treaty. It took the treaty nearly 30 years to secure universality of membership in the region.


General Conference Resolution 290 (E-VII) (1992) amended Articles 14, 15, 16, 19 and 20, reassuring the confidentiality of industrial secrets of Member States in nuclear matters and establishing how the IAEA shall intervene in the special inspections referred to in Article 12 and 13 of the Treaty.


At the XII Session of the General Conference of OPANAL, Resolution 268 (XII) amended paragraph 2 of Article 25, following the wording of Article 8 of the OAS Charter, making possible the adherence to the System of Tlatelolco of those countries which previously impeded to do so.


On 3 July, V Special Session of the General Conference Resolution 267 (E-V) (1990) amended Article 7, relating to the legal denomination of the Treaty. Once into force, the Treaty was to be titled “Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean” but was to continue to be recognized as Treaty of Tlatelolco.


Alfonso García Robles, the former Mexican ambassador to Brazil, was awarded the Nobel Peace Prize for his efforts promoting the Treaty of Tlatelolco.


The Treaty entered into force on 25 April, after 11 states of the region ratified it and exercised the right to waive requirements laid down in Article 28. Subsequently, it became effective for each additional state individually after that state ratified the Treaty and exercised its right of waiver.

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