The purpose of the research is to reveal the activities of illegal Protestant denominations in Vinnytsia region in 1945-1952 based on the analysis of the materials of the Council for Religious Cults in the Vinnytsia region; to emphasize the value of archival materials as an important type of source that reflects the specifics of the relationship between Soviet authorities at various levels and Protestant formations, as well as to emphasize the nature of the relationship between various religious associations. The research methodology is based on a combination of general scientific and interdisciplinary methodological tools. In particular, the statistical analysis and content analysis of the reports of the Authorized Council for Religious Cults in the Vinnytsia region as a historical source. Emphasis is placed on the need to free oneself from the influence of Soviet academic and social discourses, which is still manifested in the stereotypical prejudiced perception of Protestantism in the modern socio-cultural space of Ukraine. The scientific novelty is to analyze the peculiarities of the activity of illegal Protestant denominations in Vinnytsia region in 1945-1952 on the basis of the reports of the Commissioner of the Council for Religious Cults under the Soviet People's Committee of the USSR for the Vinnytsia region, which have been put into circulation for the first time. and their relationship with other Protestant currents and the Soviet authorities. Conclusions. Analyzing the activity of illegal Protestant formations in Vinnytsia in 1945-1952, the main factors of their formation and development should be noted as the border status, agrarian and multicultural nature of Podillia. The peasantry, as the main social stratum of the region, extremely exhausted by collectivization, the Holodomor-genocide, political repressions and the struggle against religion, sought spiritual protection. And it was Protestantism that managed to offer this shelter thanks to its more accessible interpretation of Christian teachings than other Christian denominations, simplified rituals, effective material support within religious communities, and well-organized underground activities. The period of Nazi occupation, which proved to be more loyal to religion than the Soviet occupation regime, only increased the number and diversified of Protestant denominations. Therefore, in the post-war years, in particular due to the manipulation of the authorities, they were unable to reach an agreement among themselves. Such incoherence in opposing the totalitarian system allowed the Soviet regime to quickly and systematically exterminate them in various ways (refusal to register, fines, moral persecution, imprisonment, etc.).