A retrospective review was performed to determine the utility of plain abdominal radiographs in evaluating children presenting to the emergency department. Clinical features, radiographic interpretation, and final diagnoses of 431 patients seen over one year were recorded. One hundred three (24%) patients had major diseases (ventriculoperitoneal shunt malfunction, foreign body ingestion, appendicitis, intussusception, bowel obstruction, necrotizing enterocolitis, toxic megacolon, blunt abdominal trauma, pyloric stenosis, and Hirschsprung's disease), while the remaining 328 (76%) had minor diseases. Radiographs were categorized as diagnostic, suggestive, normal, incidental, or misleading, with respect to the patient's final diagnosis. No single clinical feature was able to detect all diagnostic radiographs in patients with major diseases. Limiting radiographs to patients with prior abdominal surgery, suspected foreign body ingestion, abnormal bowel sounds, abdominal distention, or peritoneal signs identified all patients with radiographs diagnostic of a major disease while eliminating 48% of studies ordered. Our results suggest that restricting abdominal roentgenograms to patients with at least one of these features will detect most diagnostic radiographs in children with acute abdominal diseases.