BACKGROUND Angiodysplasia of the gastrointestinal (GI) tract is recognized as an important cause of lower GI bleeding in elderly. It usually involves the cecum and right colon in adults. Unlike the adult group, there has been little experience with the pediatric population. METHODS From July 2004 to October 2008, patients presenting at the Mackay Memorial Hospital with GI hemorrhage diagnosed as angiodysplasia by helical computed tomographic angiography were reviewed. RESULTS Eighteen patients (14 boys and 4 girls) with mean age of 7.1 years (range, 1 month to 17 years) were diagnosed. The time from initial clinical onset to diagnosis of angiodysplasia ranged from 1 week to 11 years, most around 1-2 weeks. All patients except one had anemia and an average hemoglobin level of 7.9 ± 2.1g/dL. The most commonly involved areas were ascending colon and terminal ileum. Four patients received surgery treatment with resection of affected segments. CONCLUSIONS In pediatric patients, angiodysplasia is a rare cause of GI bleeding and may be delayed in diagnosis. This diagnosis should be considered when patients have recurrent GI bleeding. In this study, the final surgical and pathological diagnosis was made in 6 of 18 patients. In six patients, computed tomographic angiography had 66% diagnostic accuracy for angiodysplasia (four of six patients who received operation were compatible with angiodysplasia by confirmation of histology).