Summary: The article is devoted to the 170th anniversary of the birth of a prominent statistician and a public figure of XIX century O.O. Rusov. The article deals with his life, presents his main publications, and describes the results of his research. The historical role of the scientist in the development of theoretical and methodological principles of statistics is discovered. The article describes the contribution to the development of scientific theory and methodology of statistical research, promotion of the use of statistical methods: grouping, generalization (relative and average values), tabular and graphical methods. Particular attention O.O. Russov gave to census, defined methodological and organizational aspects of their implementation, focused on the experience of censuses in foreign countries. In the article attention is focused on the conceptual framework of statistical observations, statistical and economic research programs of economic and social life of the provinces at the time, which were developed by scientist.
Key words: O. Rusov, statistics, statistical and economic research, theory and methodology of research.