As part of the complex expedition of St. Petersburg State University, in July 2019, field studies of the little-studied lakes of the Mongun-Taiga massif (Republic of Tuva, Russian Federation) were carried out. Hydrological and geophysical work in the massif was aimed at identifying potentially outburst hazardous lakes. Four lakes were chosen as objects for research: «Lagernoye», «Verkhneye», «Khoynur» and «Maloye», located in the valley of the south-easternmacroslope - the Tolayty river. It has been revealed that the «Lagernoye» lake belongs to the type of tarn and non-hazardous in terms of possible outbursts. Lakes «Verkhneye» and «Khoynur» are currently former glacial lakes and, subject to a combination of different circumstances, may outburst.