The Comprehensive Test Ban Treaty (CTBT) was opened for signature at the United Nations on September 24, 1996. President Clinton was the first to sign the treaty that day, followed by the representatives of 70 other nations, including Britain, France, Russia and China. To date, 155 states have signed the CTBT and 51 have ratified.
The CTBT will formally enter into force after 44 nuclear-capable states, specified in Annex 2 of the treaty, have deposited their instruments of ratification with the secretary-general of the United Nations. Those 44 states include the five declared nuclear powers, India, Israel, Pakistan and 36 other states that are recognized by the International Atomic Energy Agency as possessing nuclear power and/or research reactors.
The near-term prospects for entry into force were dealt a severe blow October 13 when the United States Senate voted against ratification of the treaty, prompting harsh international criticism and raising fears that some states might resume nuclear testing. (See press conference, and news article.) The vote came just days after states that have already ratified the CTBT held a conference in Vienna to consider measures to bring the treaty into force.
Of the 44 specified nations, all except India, Pakistan and North Korea have signed, but only 26 have ratified the treaty. Britain and France are the only declared nuclear-weapon states to have ratified. The following chart identifies the Comprehensive Test Ban Treaty's signatories and ratifiers as of October 31, 1999. States whose ratification is required for entry into force are in bold.
| Country | Signature | Ratification |
| Albania | 9/27/96 | |
| Algeria | 10/15/96 | |
| Andorra | 9/24/96 | |
| Angola | 9/27/96 | |
| Antigua and Barbuda | 4/16/97 | |
| Argentina | 9/24/96 | 12/4/98 |
| Armenia | 10/1/96 | |
| Australia | 9/24/96 | 7/9/98 |
| Austria | 9/24/96 | 3/13/98 |
| Azerbaijan | 7/28/97 | 2/2/99 |
| Bahrain | 9/24/96 | |
| Bangladesh | 10/24/96 | |
| Belarus | 9/24/96 | |
| Belgium | 9/24/96 | 6/29/99 |
| Benin | 9/27/96 | |
| Bolivia | 9/24/96 | 10/4/99 |
| Country | Signature | Ratification |
| Bosnia and Herzegovina | 9/24/96 | |
| Brazil | 9/24/96 | 7/24/99 |
| Brunei Darussalem | 1/22/97 | |
| Bulgaria | 9/24/96 | 9/29/99 |
| Burkina Faso | 9/27/96 | |
| Burundi | 9/24/96 | |
| Cambodia | 9/26/96 | |
| Canada | 9/24/96 | 12/18/98 |
| Cape Verde | 10/1/96 | |
| Chad | 10/8/96 | |
| Chile | 9/24/96 | |
| China | 9/24/96 | |
| Colombia | 9/24/96 | |
| Comoros | 12/12/96 | |
| Congo | 2/11/97 | |
| Congo Republic | 10/4/96 | |
| Cook Islands | 12/5/97 | |
| Costa Rica | 9/24/96 | |
| Cote d'Ivoire | 9/25/96 | |
| Croatia | 9/24/96 | |
| Cyprus | 9/24/96 | |
| Czech Republic | 11/12/96 | 9/11/97 |
| Denmark | 9/24/96 | 12/21/98 |
| Djibouti | 10/21/96 | |
| Dominican Republic | 10/3/96 | |
| Ecuador | 9/24/96 | |
| Egypt | 10/14/96 | |
| El Salvador | 9/24/96 | 9/11/98 |
| Equatorial Guinea | 10/9/96 | |
| Estonia | 11/20/96 | 8/13/98 |
| Country | Signature | Ratification |
| Ethiopia | 9/25/96 | |
| Fiji | 9/24/96 | 10/10/96 |
| Finland | 9/24/96 | 1/15/99 |
| France | 9/24/96 | 4/6/98 |
| Gabon | 10/7/96 | |
| Georgia | 9/24/96 | |
| Germany | 9/24/96 | 8/20/98 |
| Ghana | 10/3/96 | |
| Greece | 9/24/96 | 4/21/99 |
| Grenada | 10/10/96 | 8/19/98 |
| Guatemala | 9/20/99 | |
| Guinea | 10/3/96 | |
| Guinea-Bissau | 4/11/97 | |
| Haiti | 9/24/96 | |
| Holy See | 9/24/96 | |
| Honduras | 9/25/96 | |
| Hungary | 9/25/96 | 7/13/99 |
| Iceland | 9/24/96 | |
| Indonesia | 9/24/96 | |
| India | | |
| Indonesia | 9/24/96 | |
| Iran | 9/24/96 | |
| Ireland | 9/24/96 | 7/15/99 |
| Israel | 9/25/96 | |
| Italy | 9/24/96 | 2/1/99 |
| Jamaica | 11/11/96 | |
| Japan | 9/24/96 | 7/8/97 |
| Jordan | 9/26/96 | 8/25/98 |
| Kazakhstan | 9/30/96 | |
| Kenya | 11/14/96 | |
| Kuwait | 9/24/96 | |
| Kyrgyzstan | 10/8/96 | |
| Laos | 7/30/97 | |
| Country | Signature | Ratification |
| Latvia | 9/24/96 | |
| Lesotho | 9/30/96 | 9/14/99 |
| Liberia | 10/1/96 | |
| Liechtenstein | 9/27/96 | |
| Lithuania | 10/7/96 | |
| Luxembourg | 9/24/96 | 5/26/99 |
| Macedonia | 10/29/98 | |
| Madagascar | 10/9/96 | |
| Malawi | 10/9/96 | |
| Malaysia | 7/23/98 | |
| Maldives | 10/1/97 | |
| Mali | 2/18/97 | 8/4/99 |
| Malta | 9/24/96 | |
| Marshall Islands | 9/24/96 | |
| Mauritania | 9/24/96 | |
| Mexico | 9/24/96 | 10/5/99 |
| Micronesia | 9/24/96 | 7/25/97 |
| Moldova | 9/24/97 | |
| Monaco | 10/1/96 | 12/18/98 |
| Mongolia | 10/1/96 | 8/8/97 |
| Morocco | 9/24/96 | |
| Mozambique | 9/26/96 | |
| Myanmar (Burma) | 11/25/96 | |
| Namibia | 9/24/96 | |
| Nepal | 10/8/96 | |
| Netherlands | 9/24/96 | 3/23/99 |
| New Zealand | 9/27/96 | 3/19/99 |
| Nicaragua | 9/24/96 | |
| Niger | 10/3/96 | |
| North Korea | | |
| Norway | 9/24/96 | 7/15/99 |
| Oman | 9/23/99 | |
| Country | Signature | Ratification |
| Pakistan | | |
| Panama | 9/24/96 | |
| Papua New Guinea | 9/25/96 | |
| Paraguay | 9/25/96 | |
| Peru | 9/25/96 | 11/12/97 |
| Philippines | 9/24/96 | |
| Poland | 9/24/96 | 5/25/99 |
| Portugal | 9/24/96 | |
| Qatar | 9/24/96 | 3/3/97 |
| Romania | 9/24/96 | 10/5/99 |
| Russia | 9/24/96 | |
| Saint Lucia | 10/4/96 | |
| Samoa | 10/9/96 | |
| San Marino | 10/7/96 | |
| Sao Tome and Principe | 9/26/96 | |
| Senegal | 9/26/96 | 6/9/99 |
| Seychelles | 9/24/96 | |
| Singapore | 1/14/99 | |
| Slovakia | 9/30/96 | 3/3/98 |
| Slovenia | 9/24/96 | 8/31/99 |
| Solomon Islands | 10/3/96 | |
| South Africa | 9/24/96 | 3/30/99 |
| South Korea | 9/24/96 | 9/24/99 |
| Spain | 9/24/96 | 7/31/98 |
| Sri Lanka | 10/24/96 | |
| Suriname | 1/14/97 | |
| Swaziland | 9/24/96 | |
| Sweden | 9/24/96 | 12/2/98 |
| Switzerland | 9/24/96 | 10/1/99 |
| Tajikistan | 10/7/96 | 6/10/98 |
| Country | Signature | Ratification |
| Thailand | 11/12/96 | |
| Togo | 10/2/96 | |
| Tunisia | 10/16/96 | |
| Turkey | 9/24/96 | |
| Turkmenistan | 9/24/96 | 2/20/98 |
| Uganda | 11/7/96 | |
| Ukraine | 9/27/96 | |
| United Arab Emirates | 9/25/96 | |
| United Kingdom | 9/24/96 | 4/6/98 |
| United States | 9/24/96 | |
| Uruguay | 9/24/96 | |
| Uzbekistan | 10/3/96 | 5/29/97 |
| Vanuatu | 9/24/96 | |
| Venezuela | 10/3/96 | |
| Vietnam | 9/24/96 | |
| Yemen | 9/30/96 | |
| Zambia | 12/3/96 | |
| Zimbabwe | 10/13/99 | |
