In my habilitation I present a highly topical topic dealing with the study of selected diseases in wildlife populations in Slovakia. The aim of the habilitation thesis is to point out the significant results of monitoring selected parasitic and bacterial diseases of wildlife. Wildlife significantly affects the life cycles of parasites; as hosts and intermediate hosts, they play an important role in the circulation and spread of parasitic diseases. More than 75% of human diseases are of zoonotic origin, and it is therefore important to monitor the transmission and circulation of pathogens among wildlife, domestic and farm animals, as well as humans, especially in urban areas; targeted research must also focus on monitoring populations of vectors, parasitic arthropods in specific local conditions. The work is in the first part focused on monitoring the occurrence of selected parasitosis, such as: onchocercosis, setariosis, cysticercosis, fasciolosis and hypodermatosis in wild animals. Wildlife also plays an important role in the epidemiology and epizootiology of persistent and emerging bacterial diseases, especially as potential reservoirs of pathogens threatening the health of domestic animals and humans. Emerging infectious diseases are a global and significant health problem. In the presented second part of the habilitation thesis we summarize the results of microbiological cultivation, which proved the presence of Mycobacterium spp. in 58 (70%) samples of wild game. The A / G - ELISA protein has proven to be a sensitive and promising diagnostic tool for the serodiagnosis of Lyme disease in rats and can be used effectively for serological testing in various wild mammals. We also confirmed the occurrence of Anaplasma phagocytophilum in deer and ticks, as well as Anaplasma ovis in wildlife populations. Specific antibodies against selected species of rickettsiae and Coxiella burnetii were confirmed in samples of hunting dogs and domestic animals. These results confirm the occurrence and possible circulation of rickettsia and C. burnetii in animal and human populations in Slovakia. The obtained results support the theory of the role of deer, roe deer and fallow deer as natural reservoirs and hosts of many important pathogens.