The relevance. Radioactive elements are effective markers of the bottom sediments of Tomsk region. The aim of the research is to study radiogeochemical features of the sediments of small water reservoirs in the south of Tomsk region. The object of the study is the bottom sediments of small reservoirs in the south of Tomsk region. Methods: detailed sampling of the sediments of small reservoirs, multi-element instrumental neutron activation analysis, and data processing and interpretation by applied statistics methods. Results. We carried out radio-geochemical study of the sediments of small water reservoirs in the south of Tomsk region. Mean contents of uranium and thorium in the sediments of small reservoirs in the south of the Tomsk region were estimated. The studies showed that the uranium and thorium contents depend on the type of sediments. The highest uranium content was found in the terrigenous type of the sediments, the lowest one was found in the peat. Two zones with high uranium content were found. The first zone is spatially coinsine with Kozhevnikovsky and Shegarsky districts of Tomsk region. Osinovo-Babarykinskaya anomalous zone of uranium accumulation in this region is clearly visible, which is well seen in the submeridional direction. Within Kozhevnikovo district, it can be associated with underground water discharge in the area of the Kolyvanskiy fault. In Shegarsky district, the high uranium contents spatially relate to granitoids of the late Paleozoic Foundation. The second zone of uranium accumulation extends along the southern frame of the West Siberian plate within the Kuznetsk-Alataussky block.