The article presents the results of a study of the morphometric and hydrological features of the lakes of the Sergachsky municipal district (Nizhny Novgorod region, Russia), lying in the north of the Privolzhskaya upland. A bathymetric survey was carried out on the lakes of the researched territory from the board of an inflatable boat, using an echo sounder, combined with a navigator. The results of the field research were processed using the geographic information program QGIS, digital models of the relief of the six researched lakes were created, and their main morphometric and hydrological characteristics were calculated. Based on the analysis of the morphometric characteristics of the lakes and data on the landscape features of their surroundings, conclusions were drawn about the origin of the lake basins. Two genetic groups of lakes within the researched area are identified: karst and riverbed (oxbow lake).