Twenty-seven children aged 1 day to 16 years studied arteriographically for acute or chronic gastrointestinal bleeding were reviewed. Children with known esophageal varices and portal hypertension were excluded. Final diagnoses were made in 25 patients by means of surgery, endoscopy, biopsy, laboratory data, and clinical follow-up. Of these 25 cases, arteriography gave a correct diagnosis in 64% and was falsely negative in 36%. In acute gastrointestinal bleeding, arteriographic diagnosis was correct in 71% and falsely negative in 29%. In chronic or recurrent gastrointestinal bleeding, arteriographic diagnosis was correct in 55% and falsely negative in 45%. The common causes of bleeding in this study were gastric and duodenal ulcers, gastritis, vascular malformations, and typhlitis. Transcatheter therapy was attempted in six acute bleeders, with success in three (50%).