Аннотация:The UV-index (UVI) is a measure of the erythemally effective solar radiation reaching theEarth surface and it was introduced to alert people about the need for Sun protection. This studyapplies a model that estimates the UVI over the high Bulgarian mountains for clear sky conditionsconsidering the Total Ozone Content (TOC), which was taken from satellite measurements. Theresults show that during the periods from May to August at altitudes above 2 000 m a.s.l. high UVI’s(greater than 8) were observed for more than 18 days per month. The UVI values were high for everyday of July at altitudes higher than 1 500 m. Extremely high UVI result from episodes with TOClower than 290 DU during June and July at the highest mountain parts with elevations greater than2 500 m. High radiation risks were observed during April, especially when the preceding polar vortexwas strong and the mountains were snow covered.