The purpose of this study is to review the computed tomography (CT) appearance of gastrointestinal tract (GI) perforation. Forty-two patients with 10 cases of proximal GI perforation and 32 cases of distal GI perforation were evaluated based on the CT findings of extraluminal air (which was subdivided into the CT-falciform ligament sign crossing the midline and scattered pockets of air), bowel wall thickening (>8 mm in gastroduodenal wall, >3 mm in the small bowel wall, >6 mm in the caliber of the appendix and >5 mm in the colonic wall), associated abscess formation, ascites and adjacent fat stranding. The results were compared using Fisher's Exact Test. Detection of extraluminal air in the upright plain films and CT was analyzed by Z test. Our results showed that CT-falciform ligament sign was more frequent in the proximal GI perforation, while pockets of extraluminal air (excluding the cases accompanying CT-falciform ligament sign), bowel wall thickening and fat stranding were found in higher incidence in distal GI perforation (P<.05). CT detected extraluminal air in more cases than the upright plain films did (69% vs. 19%; Z=4.62>Z(0.01)=2.326). We concluded that CT is a good imaging tool to differentiate the various GI perforations.