Radiographic changes in 206 cases with small cavernous lesions of pulmonary tuberculosis and in 50 cases with tuberculoma which had received chemotherapy for more than 4 months were investigated, and the following conclusions were drawn. 1. Atypical shadows due to these changes were able to be classified into 5 types: string-form, asterial, club-form, motley, and lump-from. 2. The atypical shadows were observed in 17.8% of the casel with cavernous tubercular lesions and in 8% of tuberculoma cases. 3. The cavernous lesions, which were fresh with the surrounding infiltration and had a diameter less than 2cm., tended to produce the atypical shadows. The longer the duration of chemotherapy, the higher the tendency to develop the atypical shadows. It occurred most frequently in 6-8 months after the onset of treatment. Systematic treatments were proved to be superior to non-sys-tematic treatments. No difference was observed between the effect of INH and othe agents in this regard. 4. In case of tuberculoma, there was no apparent relations between the occurrence of atypical shadows and the size of lesion or the duration of treatment. The difference between the effect of INH and other agents was not observed in these cases either. 5. Tubercular bacillus was negative in the sputa of 90% of cavernous cases and 100% of tuberculoma cases which showed the atypical shadows. Most of cases with positive sputa were found to have the lump-type shadows on chest x-ray. Most of cavernous cases and some tuberculoma cases which did not show the atypical shadows had positive sputa. A large number of these positive cases showed resistance more than 10γ to any of the anti-tubercular chemotherapeutics. 6. The cavities became open again in a short time in some cases which once had had negative sputa and had shown the string-form shadows.