Seventy adult and pediatric patients with blunt splenic injury were managed nonsurgically using previously published clinical criteria without regard to the appearance of the spleen on computed tomographic (CT) scans. Seven patients (10%) who underwent delayed surgery were considered failures of nonsurgical therapy; all recovered after total splenectomy. Two radiologists, blinded to patient outcome, retrospectively reviewed the admission CT scans of all 70 patients and graded them according to three published scoring systems. Higher grades of splenic injury on CT were not associated with an increased risk of failure (Fisher's exact test, p > 0.05). Nine of ten patients with very high scores on each of the scales were successfully managed without surgery; conversely, three patients with very low scores required urgent surgery. An elevated Injury Severity Score significantly increased the risk of failure of nonsurgical management (Chi-square test of trend, p = 0.001). No failures occurred in patients under age 17 years. Our data support the hypothesis that properly selected patients can be safely observed regardless of the magnitude of splenic injury on CT scans. A decision to undergo early exploration should be based on clinical criteria, including the patient's age and associated injuries.