The presented church history research provides a specific denominational study of a post-war transition from a regional perspective. Its purpose is to reveal the process during which (in the Transcarpathian region that became part of the Soviet Union in 1944) the new state power forced the Reformed communities to accept a radical structural transformation of their church organization. In addition, it presents the violent stages of the structural transformations, during which the Soviet bureaucracy gradually suppressed the former Reformed self-administration system which had been built according to the Synod-Presbyterian principle and was based on community autonomy. The research methodology is based on the analysis of little-known and unknown archival sources of the Archives and Museum of the Transcarpathian Reformed Church, the State Archive of the Transcarpathian Region, the State Archive of the Security Service of Ukraine in Transcarpathia Region, the Central State Archives of Supreme Bodies of Power and Government of Ukraine, the Synod Archives of the Reformed Church in Hungary, and the State Archive of the Russian Federation. The scientific novelty of the research lies in the fact that the problem of the history of the Transcarpathian Reformed people after 1944 was carried out only as a partial mosaic-like study in the Ukrainian church history research along with other Protestant denominations, sometimes neglecting the chronological order and cause-and-effect relationship. Despite the fact that the history of the Protestants appears as a collective theme, or as the Protestant denomination with the largest organization, the history of the Baptists receives wide attention in the national church history writing. Our study is primarily not a factual narrative of historical chronology but rather focuses on thematic orientation. Following this point of view, it reflects on the issue (structural transformation) in the context of causality that is, when, why and how the organization of the Reformed church communities which had been based on traditional community autonomy was transferred to the hierarchical structural system. In conclusion, it can be said that the structural transformation through which the Reformed church organization underwent between February 1946 and December 1949, was a specific field for the manifestation of Sovietization. In the present study, the picture of the profound social changes that the Soviet occupation of Transcarpathia in 1944, initiated in the region clearly emerges. Based on its ideology, the openly atheistic imperial state believed that immediately after the annexation of the territory and sufficient transformations of the various denominations, it would be able to use them as ideological support in its interests. However, the Reformed church which had been built according to the council-presbyterian principle and based on the autonomy of parishes did not fit into the clearly hierarchical thinking system of the one-man dictatorship. That is why its church structure had to be transformed and adjusted to the form. Thus, the well-known and completely transparent Russian Orthodox Church served as a model for structural transformations in the Soviet imperial bureaucracy. As a result, the process of transformation of the Transcarpathian Reformed church organization into the Soviet model which ended up in the disappearance of the dioceses, deacons, the bishop, and the church districts is outlined.