Background: Spontaneous pneumothorax (SPTX) is a relatively common condition. In patients with SPTX, CT has been advocated to identify blebs and bullae (BB) to help in management planning. Purpose: The study was designed to assess our experience with CT evaluation for underlying BB in children with SPTX as compared to normal controls. Materials and methods: Forty-three children (mean age 16 years, range 13-19 years) with 50 SPTX events with both chest radiographs and CT scans were reviewed. CT findings were compared with those seen in 29 age- and gender-matched controls without SPTX. The parameters evaluated included size, number, location, and ipsi-/contralateral BB; apical lines; and surgical correlation. Results: In the study group, BB were identified in 14 imaged events (28%) (size 2.5-45 mm, one to six BB) with contralateral BB in 11 of the 14 (78.6%). All BB were confined to the apices. BB were sometimes difficult to differentiate from "apical lines" - a suspected normal variant seen in 28 imaged events (56%). Of blebs seen at surgery, 59% were identified on CT, and there were no false-positive CT findings. In the control group, no BB were identified but "apical lines" were seen in eight children (28%). Conclusion: BB were seen by CT in 28% of imaged events in children with SPTX and were always confined to the apices. When present, BB were commonly bilateral (78.6%). BB should not be confused with "apical lines," which were not only seen in 56% of imaged events in the SPTX group but also in 28% of the normal controls.