Durbachites of Třebíč massif are the most likely source of natural radioactivity of loess situated near Velká Bíteš. Increased contents of natural radioactive elements, especially of Th, there were recorded. The contents of radioactive elements go down to the east. While the contents of Th quickly fall to the 50%, contents of other radioactive elements fall about 10% less in average in the region of Moravia. Their values are alike to the values of natural radioactivity terrestrial crust. The most considerable changes occur in contents of Th. Natural radioactivity is very low in the north of Moravia and gradual losses of Th have no effect on the level of radioactivity. Redeposition of radioactive elements by wind transport is not very considerable. Increased contents of radioactive elements are detectable max. 50 km from the source rock.