Various species of free living birds play an important role in the epidemiological of avian mycobacteriosis as a source of mycobacteria. Among them of certain importance are feathered game, in this country, particularly pheasant (Phasianus colchicus) and partridge (Perdix perdix). In these species, closer contact with domestic animals can be expected. The aim of this work was to find their susceptibility to M. avium, origin and location of tuberculosis process and the occurrence of mycobacteria in organs and tissues. Moreover, in pheasants the possibility of transfer of M. avium through infected individuals to pigs and poultry. After the intramuscular infection of M. avium suspension, the local lesions developed in the point of application in pheasants after 12 days. Microscopic changes in liver and in spleen in pheasants and partridges developed after 21 days. Miliary TBC in liver and spleen and the histological changes in the intestinal wall developed after 35 days. The mycobacteria were isolated sporadic after 12 days and after 21 days they were isolated from most organs and tissues and from the intestinal contents. Peroral infection by food contaminated by TBC poultry livers caused miliary TBC in liver and spleen and TBC changes in intestinal contents in pheasants after 136 days. Mycobacteria were regularly demonstrated in organs and in intestinal contents after 160 days. This model of infection could not be evaluated in partridge, because of early deaths resulting from secondary complicated infection. After free contact between TBC poultry and pheasants and partridges, histological changes were found in spleen of pheasants and in liver of partridges after 180 days. TBC changes were found in liver of pheasants after 238 days and in the intestines of pheasants after 270 days. TBC changes were found in spleen of partridges after 250 days. The transfer of M. avium from TBC infected pheasants to pigs and poultry was successful. After 45 days of join contact among TBC pheasants, healthy pigs and poultry in stables and after further stay of pigs and poultry in contaminated environment, an allergy to tuberculin was found after 65 and 178 days, respectively. Simultaneously, the TBC changes of lymphatic glands in pigs and the TBC changes of liver and spleen in poultry were found. Our results show high susceptibility of pheasant and partridge to the infection by M. avium. The TBC changes develop in these species relatively shortly after infection and elimination of mycobacteria in faeces. Infected pheasants have ability to contaminate the environment and to transfer mycobacterial infection even after relatively short contact with pigs and poultry.