CSTO: membership history 1992–2026
CSTO began in 1992 as the Collective Security Treaty (Armenia, Kazakhstan, Kyrgyzstan, Russia, Tajikistan, Uzbekistan) and became the Collective Security Treaty Organization in 2002. In 2026 it had 6 members. Membership changed in 5 years, including the 1992 founding.
Source: The groupings’ own member lists and histories, 10 Nov 20261992–2026
Belarus, Azerbaijan and Georgia joined in 1993. Azerbaijan, Georgia and Uzbekistan did not renew the treaty and left in 1999, and the treaty's members founded the Collective Security Treaty Organization in 2002. Uzbekistan rejoined in 2006 and suspended its membership in 2012. Armenia froze its participation in 2024 but has not left.
Drafted with AI from cited sources and reviewed by the editorMap. Arrow keys move the map, plus and minus zoom, N and P step through the countries with data, Enter opens the one shown, Escape clears the selection.
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Borders show who controls an area in practice, as drawn by Natural Earth. Disputed borders are dashed. Borders shown do not imply endorsement. How we treat borders
Timeline
| 1992 | Armenia, Kazakhstan, Kyrgyzstan, Russia, Tajikistan and Uzbekistan | – | 6 | The Collective Security Treaty was signed. |
|---|---|---|---|---|
| 1993 | Azerbaijan, Belarus and Georgia | – | 9 | |
| 1999 | – | Uzbekistan, Azerbaijan and Georgia | 6 | Azerbaijan, Georgia and Uzbekistan did not renew the treaty. |
| 2002 | – | – | 6 | The treaty’s members founded the Collective Security Treaty Organization. |
| 2006 | Uzbekistan | – | 7 | |
| 2012 | – | Uzbekistan | 6 | Uzbekistan suspended its membership. |
| 2024 | – | – | 6 | Armenia froze its participation; it has not left. |
Source: The groupings’ own member lists and histories, 10 Nov 20261992–2026
Every country that has been a member
| Armenia | 1992 | 1992– |
|---|---|---|
| Kazakhstan | 1992 | 1992– |
| Kyrgyzstan | 1992 | 1992– |
| Russia | 1992 | 1992– |
| Tajikistan | 1992 | 1992– |
| Uzbekistan | 1992 | 1992–1999, 2006–2012 |
| Azerbaijan | 1993 | 1993–1999 |
| Belarus | 1993 | 1993– |
| Georgia | 1993 | 1993–1999 |