Background. The results of Mycobacterium tuberculosis susceptibility testing in 2003 were analysed in 568 (84 %) pulmonary TB definite cases in the Czech Republic. Methods and Results. The resistance on antituberculotic drugs was detected in 4,9% of TB bacilli.Most frequently, resistance on one drug – isoniazid (1,8 % of pulmonary TB definite cases) has been observed. Multidrug resistant TB was found in two cases in 2003. Conclusions. The resistance of Mycobacteria was found significantly more often in foreign-born persons with pulmonary TB (25% of strains of TB bacilli were resistant on one or more AT drugs). Resistance on AT drugs was more frequent also in previously treated TB cases, especially if the relapse occurred after 3,5 years after finishing previous treatment.

        Key words: tuberculosis, Mycobacterium tuberculosis, epidemiology, resistance, MDR TB.