The development of the epidemiology of tuberculosis in GDR from 1949 is evaluated. The factors deeply influencing incidence and prevalence of tuberculosis in GDR are: the socioeconomic development of a socialist society with continuous increase of living standard and social fonds, the state of the socialist public health system in general, and the special services and methods for the control of tuberculosis in the chest clinics and hospitals. Tuberculosis is no more a common disease in GDR. Tubercle bacilli are more ubiquitous, but are confined to distinct sources. Highest attention must be paid to the sources of infection, among them to those with tubercle bacilli already found by smear examination in the infectious cases. Microscopic examination is a very important method to find these cases. Cough and sputum exist in most cases of pulmonary tuberculosis already positive by smear examination. All these conditions must be regarded in the control of tuberculosis. The risk groups of tuberculosis (patients in the 5 years after treatment, patients with silicosis diabetes, long lasting treatment with corticosteroids, persons with contacts to infectios cases, and the so-called "Gesunde Befundträger" (healthy carriers of lesions), persons older than 65 years) amount to 7% of the population but yield more than 50% of all new cases. BCG-vaccination is of no more high importance at an annual infection rate of only 0,25% (1975), but newborns will be vaccinated. Mass X-ray examinations are no more important for finding tuberculosis; but other pulmonary diseases including bronchial carcinoma are detected by this way. X-ray examinations will remain of value in the form of aimed examinations in intervals according to the risk of disease (for tuberculosis, bronchial carcinoma). The most important method in the control of tuberculosis is the immediate treatment of all new cases. The results depend on the quality of therapy. It has to be still improved. It is the aim, to eliminate tuberculosis as a special problem of public health in GDR till 1982, 100 years after the discovery of the tubercle bacilli by ROBERT KOCH.