On September 21, 2024, the medical community celebrates the 150th anniversary of the birth of Nikolai Aleksandrovich Semashko, an outstanding manager of Russian healthcare, a scientist and teacher in the field of social hygiene. The results of his work in creating a new healthcare system in difficult conditions, one of the main principles of which is prevention, is highly appreciated by the World Health Organization and is known all over the world. To study the main directions of the prevention of various diseases over the first half of the twentieth century, there were analyzed the scientific works of N.A. Semashko, located in the electronic scientific libraries eLibrary, CyberLeninka, Scopus, Web of Science, the Central Scientific Medical Library, and the Russian State Library. N.A. Semashko considered prevention a priority in the activities of not only health professionals, but also other state and public organizations, as well as the citizens themselves in maintaining and strengthening their health. For its implementation, he recommended using various approaches, including improving the activities of sanitary organizations and medical institutions, developing dispensaries, the district principle of work, involving sanitary inspectors in joint activities with doctors and conducting health education of the population. Conclusions. Justified by N.A. Semashko in scientific works and the main directions of preventive medicine implemented in practice contributed to the elimination of epidemics, a decrease in the level of morbidity and mortality of the population, and therefore this experience should be taken into account and used in modern conditions.