The article concerns the activities of the Vilnius coadjutor, Józef Stanisław Sapieha, at the Vilnius, Smolensk and Starodub sejmiks (local assemblies) during the reign of Augustus III. The key importance of Józef Stanisław Sapieha at these sejmiks in Vilnius was revealed. The article shows that the participation of the Vilnius coadjutor at the Vilnius, Smolensk and Starodub sejmiks took various forms: direct participation, preparation of elections or the termination of the assembly, combining rivals for the election of a deputy or envoy, satisfying the protesting noblemen and formulating parliamentary instructions. Józef Stanisław Sapieha did not always win at these three sejmiks in Vilnius, but everyone had to count on his influence. Sapieha’s adversaries at these assemblies were simply supporters of the Radziwiłł family: the Żaba and Abramowicz families, as well as Mikołaj Petrusewicz, Hrehory Gimbut, Stanisław Łopot and Franciszek Tyzenhauz. They often held Vilnius castle offices under voivodes, who were the leaders of the Radziwiłł magnate party. During the cooperation of the Vilnius coadjutor with the Radziwiłł family, in alliance with their supporters, sejmiks were held peacefully in Vilnius.