The objective of the submitted work was to present a summary of basic epidemiological data in a group of 1034 subjects from whom during the period between 1968–1999 Mycobacterium kansasii was isolated. In the analysis of the group principles of the descriptive epidemiological method were used. In the first years, when diseases were recorded and the number of cases increased, epidemiologists of the District Hygiene Station in Karviná made an investigation. The objective was to describe the clinical aspect and based on epidemiological investigations to analyze data and to find an answer to basic links of the spread of infection, i.e. source, route of transmission to susceptible subjects and based on the assembled findings, to suggest the necessary epidemiological provisions. Interhuman transmission was not proved in any of the patients. The causal agent of the infection is most probably transmitted through water (by the aerogenic route). The Karviná district belongs to the largest investigated endemic areas in the world.

        Key words: endemic incidence of M. kansasii – route of transmission – susceptible subjects – classical pulmonary TB – mycobacteriosis (M. kansasii) of lungs.