In this paper, the bioclimatic analysis of the Nature Park" Zlatibor" was conducted, by using the Universal Thermal Climate Index (UTCI), which represents the heat stress of the human organism caused by meteorological conditions. The aim of the research is to monitor the annual course and changes in the values of the index, as well as the representation of the frequency of various categories of thermal stress at the seasonal level, in the period 2012-2017. For the analysis needs, daily values of meteorological data (air temperature, air pressure, relative humidity, wind speed and total cloud cover) for period of 6 years (2012-2017) were used, which were measured at the main weather station Zlatibor (1028 m). The obtained results shows a gradual change of the seasonal bioclimatic characteristics of this area. The most significant changes were recorded during the summer and early autumn, which is in line with the previous research on weather and bioclimatic conditions of the territory of the Republic of Serbia, which indicated the existence of a positive trend in the increase in average annual temperatures.