The Leningrad Affair, or Leningrad case ("Ленинградское дело" in Russian, or "Leningradskoye delo"), was a series of criminal cases fabricated in the late 1940s–early 1950s by Joseph Stalin in order to accuse a number of prominent politicians and members of the Communist Party of the Soviet Union of treason and intention to create an anti-Soviet organisation based in Leningrad.
Moscow and Leningrad were two competing power centers in the Soviet Union. Researchers[who?] argue that the motivation behind the cases was Joseph Stalin's fear of competition from the younger and popular Leningrad leaders - who had been fêted as heroes following the city's siege. Stalin's desire to keep power was combined with his deep distrust of anyone from St. Petersburg/Leningrad from the time of Stalin's involvement in the Russian Revolution, Russian Civil War, execution of Grigory Zinoviev and the Right Opposition. Among Stalin's competitors from Leningrad who were also assassinated were two former Mayors of the city: Sergei Kirov and Leon Trotsky; whose appointed subordinates continued to work in the city government for years after their own terms as Mayor ended.  During the siege of Leningrad, the city leaders were practically autonomous from Moscow and still managed to build an impenetrable defense that saved the city during the 900-days-long siege and won the battle on their own, while Stalin and his Kremlin cabinet did not control Leningrad. Survivors of the siege became national heroes, and leaders of Leningrad again gained much clout in the Soviet Federal government in Moscow.
In January 1949 Pyotr Popkov, Aleksei Kuznetsov and Nikolai Voznesensky organised a Leningrad Trade Fair to boost the post-war economy and support the survivors of the Siege of Leningrad with goods and services from other regions of the Soviet Union. The fair was attacked by official Soviet propaganda, and was falsely portrayed as a scheme to use the federal budget from Moscow for business development in Leningrad, although the budget and economics of such a trade fair were normal and legitimate and approved by State Planning Commission and the government of the USSR. Other accusations included that Kuznetsov, Popkov and others tried to re-establish Leningrad's historic and political importance as a former capital of Russia, thus competing with Moscow-centered communist government. The initial accuser was Georgy Malenkov, Stalin's first deputy. Then formal accusations were formulated by the Communist Party and signed by Malenkov, Khrushchev and Lavrentiy Beria. Over two thousand people from the Leningrad city government and regional authorities were arrested. Also arrested were many industrial managers, scientists and university professors. The city and regional authorities in Leningrad were swiftly occupied by pro-Stalin communists transplanted from Moscow. Several important politicians were arrested in Moscow and other cities across the Soviet Union.
As a result of the first prosecution, on 30 September 1950, Nikolai Voznesensky (chairman of Gosplan), Mikhail Rodionov (Chairman of the RSFSR Council of Ministers), Aleksei Kuznetsov, Pyotr Popkov, Ya. F. Kapustin and P.G. Lazutin were sentenced to death on false accusations of embezzlement of the Soviet State budget for "unapproved business in Leningrad", which was labeled as anti-Soviet treason.
The verdict was announced behind closed doors after midnight and the six main defendants, including the mayor of the city, were executed by shooting on 1 October 1950. Stalin's government had reinstated the death penalty in the Soviet Union on 12 January 1950; it had previously been repealed in 1947. It was applied to the accused retroactively. Over 200 Leningrad officials were sentenced to prison terms from 10 to 25 years. Their families were stripped of rights to live and work in any major city, thus limiting their lives to Siberia.
About 2,000 of Leningrad's public figures were removed from their positions and exiled from their city, thus losing their homes and other property. All of them were repressed, together with their relatives. Respected intellectuals, scientists, writers and educators, many of whom were pillars of the city's community, were exiled or imprisoned in the Gulag prison camps. Intellectuals were harshly persecuted for the slightest signs of dissent, such as Nikolai Punin, who was killed in a prison camp for expressing his dislike of Soviet propaganda and thousands of Lenin's portraits.
Simultaneously, the Soviet authorities replaced all administrative leadership in Leningrad by communists loyal to Stalin. Upon Stalin's approval, Malenkov personally ordered the destruction of the Museum of the Siege of Leningrad and declared the 900-day-long defence of Leningrad "a myth designed by anti-Soviet traitors trying to diminish the greatness of comrade Stalin."
The Leningrad affair was organised and supervised by Malenkov and Beria[dubious ]. Executions and purges were done by Viktor Abakumov and the MGB. Graves of executed leaders of Leningrad were never marked and their exact locations are still unknown.
- Dmitri Volkogonov, Stalin: Triumph and Tragedy, 1996, ISBN 0-7615-0718-3
- Leon Trotsky. Kirov Assassination. 1934. 
- "The Affair of Leningrad Centre...", from Russian Encyclopedia Krugosvet (Russian)
- Edvard Radzinsky, Stalin: The First In-depth Biography Based on Explosive New Documents from Russia's Secret Archives, 1997, ISBN 0-385-47954-9
- Malenkov against Zhdanov. Games of Stalin's favourites. (Russian)
- The "Leningrad Affair" (Russian)
- Leningrad Affair and the Provincialization of Leningrad. 
- Stalin and the Betrayal of Leningrad by John Barber
- N.F. Kuznetsova and I.F. Tyazhkova (ed.). "7 Военное и послевоенное уголовное законодательство (1941-1945 гг. и 1945-1953 гг.)". Курс уголовного права. Том 1. Общая часть. Учение о преступлении (in Russian). I.F. Zertsalo. p. 2002. ISBN 5-94373-034-6.
- "«Ленинградское» дело (политический процесс 40-50 гг. XX века)". Memorial.
- Pazin, Mikhail (2012). "«Ленинградское дело»". «Страсти по власти: от Ленина до Путина» (in Russian). ISBN 978-5-459-01201-9.
- The Diaries of Nikolay Punin: 1904-1953. University of Texas Press (1999) ISBN 0-292-76589-4
- William Taubman, Khrushchev: The Man and His Era, London: Free Press, 2004