Horses are characterized by a very high incidence of mycoses in comparison with most livestock and companion animals. They are highly susceptible to asymptomatic infections caused by yeast-like fungi, but the carrier state may be disrupted under the influence of autogenic and allogenic factors. The above leads to severe organ mycoses, often with an acute form of infection. "Carrier horses" may also act as vectors which transmit potential pathogens between individuals and species. The aim of this study was to identify yeast-like fungi and yeast colonizing the ontocenoses of healthy horses and to determine the factors which affect the frequency of pathogen isolation. It was noted that the age of the horses influenced the frequency of isolating fungi and the species diversity of obtained isolate. The taxonomical spectrum of fungi also varied depending on the season (in the autumn: 37 species, in the spring: 8 species). The results of the experiment indicate that fungi colonizing the mucosa and skin of animals have a broad taxonomic spectrum. The prevalent fungi were members of the genera Candida, represented by 12 species, and Saccharomyces, represented by 5 species. The most frequently isolated species were: Candida krusei (49 isolates) and Saccharomyces cerevisiae (40 isolates). Many species have been isolated from horses for the first time, which indicates the scarcity of research in this area and the need for routine observations of the mycological environment of stables.