The medical records of 158 patients with perirenal hematoma found during laparotomy for intra-abdominal injury from external trauma were analyzed. Small perirenal hematomas were usually associated with renal contusions and renal artery thrombosis, while large perirenal hematomas often were present with large renal lacerations, renal ruptures, and renal pedicle injuries with rupture of the renal vein, renal artery, polar artery, or branch of the renal artery. The management of the perirenal hematoma found during laparotomy depends on the degree of the underlying renal injury and not on the size or extent of the perirenal hematoma.