Abstract: The subject of this article is the analysis of the history of relations between M. M. Prishvin and N. A. Semashko since gymnasium childhood until the last days of life. It is demonstrated that if the biographical material on enduring friendship between Prishvin and Semashko, contained in reminiscences of their contemporaries and works of the writer himself, is given considerable attention, then his diary notes, which significantly transform the representations on true nature of their relations, have not yet become the subject of research. The article employs the method of historical reconstruction of ideological-political context of life of the Soviet society, which gives a better perspective on the peculiarities of artistic interpretation by M. M. Prishvin of the party and state activity of N. A. Semashko. The novelty of this article consists in introduction into the scientific discourse of the new facts from Prishvin’s Diary that consisted of 18 volumes and was published only in post-Soviet time  (1991-2017), which is a testimony that his relations with the People's Commissar of Public Health N, A, Semashko were often tainted with irreconcilable ideological and worldview discrepancies. It is no coincidence that in his autobiographical novel “The Chain of Kashchei”, Prishvin portrayed Semashko not only as an ideological supporter of Leninism, but also a nihilist-Nietzschean Yefim Nesgovorov. Morveover, the history of relations with Semashko sheds light on the reasons of Prishvin's disappointment with the revolutionary ideology of Bolshevism.