In July 1920, the 11th Soviet Red Army invaded and occupied the region and on July 28, declared the Nakhchivan Autonomous Soviet Socialist Republic with "close ties" to the Azerbaijan SSR. In November, on the verge of taking over Armenia, the Bolsheviks, in order to attract public support, promised they would allot Nakhchivan to Armenia, along with Karabakh and Zangezur. This was fulfilled when Nariman Narimanov, leader of Bolshevik Azerbaijan issued a declaration celebrating the "victory of Soviet power in Armenia," proclaimed that both Nakhchivan and Zangezur should be awarded to the Armenian people as a sign of the Azerbaijani people's support for Armenia's fight against the former DRA government:
“ As of today, the old frontiers between Armenia and Azerbaijan are declared to be non-existent. Mountainous Karabagh, Zangezur and Nakhchivan are recognised to be integral parts of the Socialist Republic of Armenia.[43][44] ”
Vladimir Lenin, although welcoming this act of "great Soviet fraternity" where "boundaries had no meaning among the family of Soviet peoples," did not agree with the motion and instead called for the people of Nakhchivan to be consulted in a referendum. According to the formal figures of this referendum, held at the beginning of 1921, 90% of Nakhchivan's population wanted to be included in the Azerbaijan SSR "with the rights of an autonomous republic."[43] The decision to make Nakhchivan a part of modern-day Azerbaijan was cemented March 16, 1921 in the Treaty of Moscow between Bolshevist Russia and the newly-founded Republic of Turkey. The agreement between the Soviet Russia and Turkey also called for attachment of the former Sharur-Daralagez uyezd (which had a solid Azeri majority) to Nakhchivan, thus allowing Turkey to share a border with the Azerbaijan SSR. This deal was reaffirmed on October 23, in the Treaty of Kars. Article V of the treaty stated the following:
“ The Turkish Government and the Soviet Governments of Armenia and Azerbaijan are agreed that the region of Nakhchivan, within the limits specified by Annex III to the present Treaty, constitutes an autonomous territory under the protection of Azerbaijan. ”
So, on February 9, 1924, the Soviet Union officially established the Nakhchivan ASSR. Its consititution was adopted on April 18, 1926.
在1920年决定建立纳希切万苏维埃社会主义自治共和国的时候，它是声称和阿塞拜疆苏维埃社会主义共和国有着“紧密联系”的。同年11月亚美尼亚取得苏维埃革命胜利。为了庆祝这一胜利，阿塞拜疆领导人Nariman Narimanov决定将纳希切万和纳格尔诺-卡拉巴赫送给亚美尼亚，以换取亚美尼亚对反击原资产阶级政权阿塞拜疆民主共和国的武力支持。这一决定也得到列宁首肯。尽管纳希切万曾为此于1920年初进行全民公决，90%以上民众支持留在阿塞拜疆成为自治共和国，并且根据苏俄与土耳其1921年订立的和约，纳希切万也属于阿塞拜疆苏维埃社会主义共和国的一部分，但是1924年正式建立的时候还是划给了亚美尼亚。
