In the beginning of 1930s, institutions like Association for Contemporary Music and the Russian Association of Proletarian Musicians were closed down with the aim of gathering every study of music under one center, and under the control of the Communist Party. As a result, all the studies were realized within the two organizations of the Composers’ Union in Moscow and Leningrad in 1932, which later merged to form the Union of Soviet Composers in 1948. In 1948, composer Tikhon Khrennikov (1913-2007) was appointed as the first president of the Union of Soviet Composers by Andrei Zhdanov and continued this post until the collapse of the Soviet Union in 1991. Being one of the most controversial figures in the history of Soviet music, Khrennikov became the third authority after Stalin and Zhdanov in deciding whether a composer or an artwork should be censored or supported by the state. Khrennikov’s main job was to ensure the application of socialist realism, the only accepted doctrine by the state, on the field of music, and to eliminate all composers and works that fell out of this context. According to the doctrine of socialist realism, music should formalize the Soviet nationalist values and serve the ideals of the Communist Party. Soviet composers should write works with folk music elements which would easily be appreciated by the public, prefer classical orchestration, and avoid atonality, complex rhythmic and harmonic structures. In this period, composers, performers or works that lacked socialist realist values were regarded as formalist. Khrennikov’s big war against formalism started at the first congress of the Union of Soviet Composers held in April 1948. The process that started with the castigation of some important composers including Shostakovich, Prokofiev and Khachaturian, lasted until the ban of the seven composers interested in innovative music trends in 1979, who are also known as the Khrennikov Seven. Comprised of Elena Firsova, Dmitri Smirnov, Alexander Knaifel, Viktor Suslin, Vyacheslav Artyomov, Sofia Gubaidulina and Edison Denisov, the Khrennikov Seven were condemned for attending some festivals in the West without permission, and their music was addressed as “meaningless and loud” by Khrennikov. These composers also had to endure travel and performance bans. In this article, Khrennikov’s sanctions of 1948 and 1979, and their effects on composers and Soviet music in broad sense are analyzed.