Between November 1979 and September 1984, ten adults with documented traumatic injuries of the spleen were treated nonoperatively at The Johns Hopkins Medical Institutions. The mechanisms of injury varied from assaults with a blunt object to a low-velocity motor vehicle accident. Diagnosis was confirmed in all with computed tomography of the abdomen. Seven patients were successfully managed nonoperatively. The hospital course in these seven patients was uncomplicated with a mean hospital stay of 10 days. Three patients underwent splenectomy after failure of nonoperative management; two operations were performed semielectively and one as an emergent procedure. In the latter patient, the diagnosis of splenic rupture was made 7 days after the injury and was not suspected on initial presentation. The limited experience suggests that adults selected for nonoperative management should fulfill certain criteria that include 1) rapid hemodynamic stabilization after fluid resuscitation, 2) lack of other serious intra-abdominal injuries, 3) lack of extra-abdominal trauma that requires a prolonged general anesthetic or that results in an altered state of consciousness, and 4) progressive symptomatic improvement early during the hospitalization. Patients involved in high-speed motor vehicle accidents should not be considered as candidates because of the high prevalence of other serious injuries. From these guidelines, the results support the concept of nonoperative management of selected adults with splenic injury.