The patient was a 20-year-old woman with spontaneous pneumothorax, who had had pneumothorax twice on each side. Three-dimensional computed topographic (CT) images were made as follows. The range 12.5 cm caudad from the pulmonary apex was scanned by rapid helical CT, and three-dimensional images were obtained with the surface-rendering technique at a voxel extraction threshold ranging-850 HU to 1,600 HU. The three-dimensional CT images provided a stereotactic rendering of the lung surface. Irregular findings were observed at both pulmonary apices; they indicated the presence of one emphysematous bulla in the right lung and many emphysematous bullae of various sizes in the left lung. These findings were highly consistent with the sites and structures of the emphysematous bullae, as observed during thoracoscopy, which suggests that three-dimensional CT is a useful method for diagnosing and evaluating emphysematous bullae in patients with spontaneous pneumothorax.