This article focuses on the influence of Western progressive rock music on some innovative members of the Union of Soviet Composers, who were open to new trends and influences. These Soviet composers’ interest in progressive rock was not only intellectual, but also had serious practical implications. During the 1970s, several composers made attempts to create original works following various styles of prog rock. Occasionally, they incorporated elements of prog rock into their otherwise experimental compositions. One can see the influences of prog rock in the works of prominent composers such as A. Pärt, S. Gubaidulina, V. Martynov, V. Silvestrov, V. Artemiev, G. Kancheli, and A. Schnittke. After discussing the development of the prog rock tradition in the USSR and dwelling on the peculiarities of prog rock as a genre, I focus on three works created by Soviet composers under the influence of prog traditions: the 4th Symphony for orchestra and rhythm section by Latvian composer Imants Kalniņš, which follows the traditions of symphonic rock; an avant-garde rock opera titled “Flemish Legend” by Leningrader Romuald Grinblat, written to the lyrics by dissident bard Yulii Kim and heavily influenced by the twelve-tone system; and a suite of art-rock songs titled “On the Wave of My Memory” composed by pop composer David Tukhmanov, based on the poems of poets with a “decadent” reputation in the Soviet ideological context. All of these composers had to create within the Soviet ideological restrictions on modern and rock music, in particular, and all of them had to engage in their own trickster-like antics to produce and perform their works. Although they are little remembered today, these works stand as unexpected and singular achievements of Soviet composers during complex times.