Objective: To evaluate changes of chest CT findings in patients with active pulmonary tuberculosis (TB) between before and after anti-TB chemotherapy and the usefulness of chest CT scan to assess the persisted disease activity or possibility of early reactivation. Materials and Methods: We retrospectively reviewed newly diagnosed 67 pulmonary TB patients who received standard short-course chemotherapy. Chest CT scans were performed before and after treatment. Results: Tree-in-bud appearance lesion (84%), peribronchial consolidation (64%), pre-existing old TB lesion (37%), cavitation (28%), and larger confluent density including lobular consolidation (27%) were most common findings on chest CT scan at starting of anti-TB therapy. After completion of anti-TB therapy, regressions of initial parenchymal findings were found in the most patients (87%, 58/67) without new or aggravated lesion. Newly appeared and/or aggravated splenic tuberculomas (1/67), TB lymphadenitis (1/67), cavitary nodules (4/67), and tree-in-bud appearance lesions (2/67) after 6 months therapy, were completely treated with or without additional 3 months therapy (total 9 months therapy). Among all patients with median 15 months (IQR 10-21 months) follow up after completion of anti-TB therapy, only 1 patient relapsed despite regression of initial active lesions after 6 months treatment. Conclusions: If initial parenchymal lesions were regressed after sufficient TB therapy, new cavitation or residual lesions were not suggestive of persisted activity or possibility of early reactivation of pulmonary TB.