The article is devoted to the scientific and practical activities of the prominent representative of the school of political arithmetic W. Petty. He was a well-known English economist, physician, inventor of copying equipment, doctor of physics, professor of astronomy, founder of English classical political economy, statesman, one of the founders of the Royal Society of London. In the article the biography of W. Petty is outlined and his role in the formation of scientific statistics is considered. The main works of the scientist such as: “Political arithmetic”, “A Treatise of Taxes and Contributions”, “Verbum Sapienti posthum”, “Political anatomy of Ireland” are analyzed. The views of the scientist on a wide range of socio-economic problems of the time and directions of their solution are considered Petty’s contribution to the development of methodological foundations of statistical science is determined. The article emphasizes the historic merit of the scientist in creating the basis of the statistical- economic method of research. The focus was made on W Petty’s application of the methods of collecting, processing, systematization and generalization of statistical information. W Petty first calculated the magnitude of the national wealth of England and Wales and made calculations of the national income, as well as differentiated these concepts and paid attention not only to the monetary form, but also material. In essence, from these calculations we can speak about the emergence of the foundations of the modern system of macroeconomic national accounting. It was also a great achievement of W Petty that he identified his main task of studying the laws of social phenomena. He was the first to raise the issue of the necessity of establishing a state statistical service and outline outlined its main activities. His achievements of the scientist concerning forecasting and comparative characteristics of the population of large cities of Europe are also considered. The article reflects the thoughts and statements of the descendants of W Petty, well-known researchers in the history of statistics, who highly appreciated the role and contribution of the scientist in the formation of statistical science.