PURPOSE: This study was performed to examine if CT classification of renal blunt injury could aid in expectation of hemodynamic stability and clinical decision of whether to intervene surgically. MATERIALS AND METHODS: Over a 80-month period between July 1987 and March 1994, 41 patients were admitted to our hospital with the diagnosis of renal blunt injury. The renal blunt injuries were classified on Fedede's three-point scale CT classification methods :grade I, contusion, intrarenal hematoma, segmental infarction, and small subcapsular hematoma;grade II, complete or incomplete laceration, large subcapsular hematoma, and renal fracture;grade Ill, shattered kidney and renal pedicle injury. Hemodynamic stability, treatment method and clinical outcome of the patients with different CT grade were analyzed retrospectively. RESULTS: All 34 patients with grade I or II CT findings were hemodynamically stable and were successfully managed with conservative method. Among 7 patients with grade III CT findings, 6 patients were hemodynamically unstable. Out of the 6, One patient with grade IIIb or renal pedicle injury was expired before surgical intervention due to ischemic shock. Four patients were intervened surgically with one failure to thrive. The remaining one patient refused to be intervened surgically, and was discharged against medical advice. Only one out of 7 patients was hemodynamically stable and was managed conservatively. CONCLUSION: The patients with grade I or II CT findings are prone to be hemodynamically stable and to be managed with conservative method. But the patients with grade III CT findings are more likely to be hemodynamically unstable. Therefore patients with grade III CT findings should be closely monitored and be pre- pared for the possibility of immediate surgical intervention.