Overview
As of the last census in 1988, the Soviet Union had a population of 286.717 million in its 15 Union republics. The Russian SFSR (Russian Soviet Federative Socialist Republic) was the largest Union republic in terms of both area and population, and the dominant one in political and economic terms.
Development
The number of inhabitants increased dramatically in 1940 due to the annexation of the three Baltic states and the Moldavian region, as well as due to the expansion of the Belarusian and Ukrainian territories at the expense of Poland. The very high number of war victims (soldiers as well as civilians) from 1941 to 1945 was the reason for the decrease in the number of inhabitants.
| Population development in million |
| Republic | 1913 | 1926 | 1939 | 1950 | 1959 | 1966 | 1970 | 1973 | 1979 | 1987 | 1988/89 | 1991 |
| Russian SFSR (RSFSR) | 89,900 | 92,737 | 108,379 | | 117,534 | 126,561 | 130,079 | 132,151 | 137,410 | 145,311 | 147,386 | 148,548 |
| Ukrainian SSR | 35,210 | 29,515 | 40,469 | | 41,869 | 45,516 | 47,127 | 48,243 | 49,609 | 51,201 | 51,704 | 51,944 |
| Belarusian SSR | 6,899 | 4,983 | 8,910 | | 8,055 | 8,633 | 9,002 | 9,202 | 9,533 | 10,078 | 10,200 | 10,260 |
| Uzbek SSR | 4,366 | 4,660 | 6,440 | | 8,261 | 10,581 | 11,960 | 12,902 | 15,389 | 19,026 | 19,906 | 20,708 |
| Kazakh SSR | 5,565 | 6,037 | 5,990 | | 9,154 | 12,129 | 12,849 | 13,705 | 14,684 | 16,244 | 16,538 | 16,793 |
| Georgian SSR | 2,601 | 2,677 | 3,540 | | 4,044 | 4,548 | 4,686 | 4,838 | 4,993 | 5,266 | 5,449 | 5,464 |
| Azerbaijan SSR | 2,339 | 2,314 | 3,205 | | 3,698 | 4,660 | 5,117 | 5,420 | 6,027 | 6,811 | 7,029 | 7,137 |
| Lithuanian SSR | | | 2,880 | | 2,711 | 2,986 | 3,128 | 3,234 | 3,392 | 3,641 | 3,690 | 3,728 |
| Moldovan SSR | 2,056 | | 2,452 | 2,290 | 2,885 | 3,368 | 3,569 | 3,721 | 3,950 | 4,185 | 4,341 | 4,366 |
| Latvian SSR | | | 1,885 | | 2,093 | 2,262 | 2,364 | 2,430 | 2,503 | 2,647 | 2,681 | 2,681 |
| Kyrgyz SSR | 0,864 | 1,002 | 1,458 | | 2,066 | 2,652 | 2,933 | 3,145 | 3,523 | 4,143 | 4,291 | 4,422 |
| Tajik SSR | 1,034 | 1,032 | 1,484 | | 1,981 | 2,579 | 2,900 | 3,194 | 3,806 | 4,807 | 5,112 | 5,358 |
| Armenian SSR | 1,000 | 0,881 | 1,282 | | 1,763 | 2,194 | 2,492 | 2,672 | 3,037 | 3,412 | 3,283 | 3,376 |
| Turkmen SSR | 1,042 | 0,998 | 1,252 | | 1,516 | 1,914 | 2,159 | 2,364 | 2,765 | 3,361 | 3,534 | 3,576 |
| Estonian SSR | | | 1,052 | | 1,197 | 1,285 | 1,356 | 1,405 | 1,465 | 1,556 | 1,573 | 1,582 |
| Total | 159,200 | 147,028 | 190,678 | 178,500 | 208,827 | 231,868 | 241,720 | 248,626 | 262,085 | 281,689 | 286,717 | 289,943 |
Religion
The state doctrine of the Soviet Union was atheistic. The practice of religion was at times forbidden or subject to extensive state restrictions; for example, there were laws against the public singing of religious songs.
While around 1920 about 90% of the people in the Russian SFSR still belonged to the Russian Orthodox Church, by 1940 the number had fallen to less than 30%. Many believers were subjected to reprisals, tortured, shot or exiled to Siberia.
Under Lenin's leadership, the Soviet government issued decrees and laws ("Decree on Freedom of Conscience, Church and Religious Associations" of January/February 1918 and the Liquidation Law of July 27, 1918, presented by People's Commissar for Justice Pyotr Stuchka) that formally granted freedom of worship while expropriating the churches. In fact, the churches were seen as representatives of the old order and their adherents as counter-revolutionaries. As a result, there were mass executions of priests of the Russian Orthodox Church.
Under Joseph Stalin, thousands of priests were deported to labor camps (Gulag). Likewise, in Central Asian republics where Muslims were the majority, most mosques were closed and the practice of religion was also banned.
In Siberia, especially south of Lake Baikal, there are also many Buddhists. Large parts of the Korean minority also professed Buddhism.
During the Second World War, the strict state anti-religious attitude was somewhat relaxed. Some bishops and priests were released from prison. Some ecclesiastical colleges were readmitted, as well as churches and monasteries. After Nikita Khrushchev came to power, a new wave of anti-religious struggle was unleashed. Khrushchev promised to show the last priest of the Soviet Union on television soon. Under Mikhail Gorbachev in the late 1980s, state attitudes relaxed again until finally, with the collapse of the Soviet Union, freedom of religion was formally granted. However, this was interpreted in different ways. In 2018, at least five successor republics remain on Open Doors' World Persecution Index of countries with Christian persecution, including Uzbekistan in 16th place (out of 50).
See also: Persecution of Christians in the Soviet Union and Association of Fighting Godless People