The aim of the diploma thesis is to evaluate the abundance, density and favourable status of the brown bear (Ursus arctos) in Slovakia, with focus on selected areas in Kremnické vrchy, Poloniny National Park and Tatra National Park. We have studied the literature and in the individual chapters we got acquainted with the biology, ecology, economic importance of the brown bear and monitoring methodologies. We also got acquainted with the issue of bears with synanthropic behavior, negative civilizational influences and other essentials of life of this species. In the practical part of the diploma thesis, we got acquainted with individual areas, natural, climatic and orographic conditions, local fauna and flora and factors that negatively affect the brown bear. We evaluated the favourable status of bears in hunting districs in the commercial forests of the University Forest Enterprise of the Technical University in Zvolen and Makovisko, and also in the protected areas of National Parks in huting district Poloň (Poloniny National Park) and hunting district Jamnický (Tatra National Park). We evaluated the abundance, population density, population structure, population trend, areal trend, species threat, food habitat threat and reproductive habitat threat. Then we compared the favourable status of bears and negative civilization factors in the monitored areas. The population density in hunting district University Forest Enterprise is 102,38 individuals per 100 km2 of habitat. The population trend is increasing and since 2015, the number of bears has doubled. The density of individuals is very high. The population density in hunting district Makovisko is 21,96 individuals per 100 km2 of habitat and the population trend is increasing. In Poloniny National park hunting district Poloň, the density of bears is 20,85 individuals per 100 km2 of habitat. In 2020 the population trend was declining, but the population is stable with seasonal changes. In Tatra National par in hunting district Jamnický, the population density is 80,81 individuals per 100 km2 with and increasing population trend. An important finding is the higher presence of bears in lower localities. We evaluated the development of the population in Slovakia according to data from hunting statistical yearbooks in the years 2010 – 2019 and the development and status of the population in selected hunting districs from 2015 to 2020. The population in Slovakia is increasing and abundance is favourable.