The study aimed at assessing the frequency and type of errors in the diagnosis and management of newly registered bacteriologically negative cases of pulmonary tuberculosis. Random sample of 560 out of 7272 such patients registered in 1993 was subject of detailed analysis of all available medical documentation. The analysis was performed by an independent team of three specialists: pulmonologist, radiologist and epidemiologist. The results of the analysis indicate insufficient utilization of modern available diagnostic methods. Apart from clinical assessment the main basis for diagnosis of tuberculosis was A-P radiography. Tomography examination was performed in 35.5% of patient only, bronchoscopic in 19.8% and cytologic examination of sputum in 15.9%. Bacteriological examinations during the first phase of diagnosis, usually in hospitals, were satisfactory. Error in diagnosis was found in 63 patients, i.e. 11.3% of cases. The treatment in patients considered as correctly diagnosed, was in the intensive phase correct, but in the continuation phase--too long.