The bachelor's thesis "Snow conditions in BR Poľana in relation to roe deer" in the theoretical part deals with the issue of snow cover, its modification in the forest environment and the influence of snow and minimum air temperatures on the conditions of roe deer (Cervus elaphus L.) in winter season in an area of the Poľana Biosphere Reserve. The creation of water reserves is influenced not only by altitude, but also by the exposure of slopes. The measurements were carried out on the north and south oriented slopes of the caldera of the Poľana Mts. Within each research area, the characteristics of snow cover in beech, spruce stand and on a parallel open area were obtained. Furthermore, the winter severity index (WSI) of the roe deer survival was analysed, which was evaluated for three areas differentiated according to altitude (368 to 715 m a. s. l.). Based on the results, it is stated that roe deer have the most suitable biometeorological conditions for overwintering in the upland area of the Poľana. As the altitude rises, the WSI index reaches a more unfavorable value for overwintering.