To document the severity and degree of renal injury multiple studies may be necessary, including excretory urography, nephrotomography and arteriography. Even these extensive studies fail at times to provide sufficient information for treatment of the injury. The need for a more accurate noninvasive modality led us to investigate the use of computerized tomography. We used computerized tomography and excretory urography, and/or nephrotomography in 24 patients suspected of having major renal injury. Computerized tomography clearly separated minor injuries (superficial laceration) from major injuries (deep lacerations or laceration with extravasation). Computerized tomography demonstrated extravasation of opacified urine not noted on excretory urography in 5 cases. In all cases renal lacerations, and perirenal and intrarenal hematomas were defined clearly on computerized tomography. Computerized tomography provided information for proper management in all instances (18 nonsurgical and 6 surgical procedures) and all computerized tomography findings were confirmed at operation. Concomitantly, computerized tomography detected liver, spleen or pancreas injuries in 4 patients. Computerized tomography provides a highly sensitive and accurate method to evaluate renal trauma, which allows the surgeon to make a confident choice of treatment.