Type III renal injuries, deep cortical lacerations with or without urinary extravasation, have traditionally been managed by exploration and surgical repair. With improved and readily available radiologic imaging modalities such as computed tomography and intravenous pyelography, we propose that the majority of these injuries can be followed expectantly with delayed intervention as needed. The records of 71 patients with both blunt abdominal and penetrating trauma with suspected significant renal injuries were reviewed. Eighteen patients (nine blunt and nine penetrating trauma) with type III injury were identified. Thirteen patients had their renal injuries treated conservatively and three patients underwent immediate surgical repair. Two patients died of associated injuries shortly after arrival at the emergency room. Two of the conservatively treated patients and one who had initial repair needed subsequent intervention, but no renal unit was lost because of delayed intervention. Thus, of the 16 surviving patients with type III injuries, 13 (81%) were successfully managed conservatively without the need for surgical intervention. With the aid of computed tomography, conservative therapy for severely injured kidneys can yield favorable results and save patients from unnecessary exploration and possible renal loss.