The research objective is to analyse Jewish entrepreneurial activity in early modern Volynian towns and to clarify its significance for their economic development. The article methodology is guided by the principles of historicism, systematicity, scientificity and comprehensiveness. Such methods as historical and comparative, problem-chronological and retrospective were applied as well. The scientific novelty consists in the integral review of the source base of the problem which allowed presenting a wide range of Jewish commercial and industrial activities in the Volynian towns and showing its importance for the economic development of the region. Conclusions. Thorough study of the sources let for confirming the important role of Jews in the economic life of Volyn during the specified time. First of all its trading activity, though it wasn't always purely trading, but mostly combined with other types of business. Part of the Jewish population was engaged in crafts, usually connected with leather (shoemakers and skinners) and somewhat lesser number of Jews was engaged in farming. The organisation of the production of ash, soda, alcohols distillation, mead and beer brewing and their sale was popular among the Jews. The Jews kept tenement houses, were active in lending money, and engaged in driving the cattle for sale. The renting activities of the Jews were successful too. They rented duties, taverns, mills, malting and wax refineries, bridges, crossing sites and pond draining activities. What was popular was renting of a measuring levy, beverage industry levies, Schoss levies, castle and gmina revenues. Villages and cities were often rented. Sub-renting was also well-known. Not only things and houses, but also villages and cities were mortgaged to the Jews. All of this allowed collecting and accumulating large capitals. [ABSTRACT FROM AUTHOR]