The article provides an overview of primary and aggregated materials census of the Russian Empire in the second half of the 19 century, containing information about classes and professions. The article reveals the peculiarities of employment and various aspects of the employment in the census of different levels. The most informative in terms of taking into account the professional activities of the population was urban census. The analysis of statistical data revealed the features of the professional characteristics of the population and certain aspects of employment, and provided a technique used for keeping a record on the professional data. The materials of the first general census of population in 1897 present a special interest in context of employment research. The emphasis is made on the use of aggregated census data to study the question posed. The research of the aggregated data of the 1897 census allowed creating a secondary source — a database to implement new methods of analysis of statistical information. The use of additional statistical sources and the use of new information technologies will in the future conduct a multivariate statistical analysis and typology of employment of the population of the Russian Empire in the second half of 19th-early 20th centuries.