Research priorities of Alexei Nikolaevich Sysin (1879-1956) were faced to the study of issues of sanitary and epidemiological welfare of Russia. World- renowned hygienist scientist was the one of the pioneers in the field of general and communal hygiene, epidemiology and disinfection. Not little attention A.N. Sysin paid also to issues of occupational health, together with other scientists he laid the foundation of modern Occupational Health. The victory of the Great October Revolution has set before organizers and medical science scholars, among who was A.N. Sysin, new challenges in dealing with the many complex issues, including occupational health issues. Already in the first months of the new Republic he prepared dozens of directives, regulations and instructions, wrote a large number of draft laws for health services, developed the first regulations on the sanitary supervision of the country enterprises. The leading role in the emergence of many printed newspapers and magazines, books and bulletins on general issues in health, preventive medicine, hygiene, epidemiology, occupational health is belonged to A.N. Sysin. He published more than 250 scientific papers on various aspects of sanitary science: from the problems of epidemics of dangerous infections to the working and living conditions of different enterprises. A. N. Sysin paid a lot of attention to industrial injuries, problems of increscent occupational toxicology, the introduction of newest forms of general and personal protective equipment at the plant, modernization of the industrial equipment, issues of the shortened workday, labor of women and children - all kinds of sanitary measures and improvement of labor and living workers' conditions.