Renal artery branch injury resulting from stab wounds of iatrogenic origin or street violence is an important cause of renal hemorrhage. Over a period of 10 years we accurately diagnosed the injury and successfully managed the associated hemorrhage in 15 patients by using angiography and percutaneous embolization techniques. Nine branch injuries in eight patients were due to street knifings and seven injuries were complications of invasive medical procedures (four from renal biopsy, two from nephrostolithotomy, and one from nephrostomy). All patients had gross hematuria at the time of angiographic evaluation. False aneurysms were present in six patients (one with associated frank extravasation), false aneurysm/arteriovenous fistula in three, false aneurysm/arteriocaliceal fistula in one, and isolated arteriovenous fistula in two. Frank extravasation without associated false aneurysm/arteriovenous fistula was present in two. One patient had two injuries, an upper-pole false aneurysm and a lower-pole false aneurysm/arteriovenous fistula. In the eight patients injured in street knifings, hematuria recurred after surgical exploration and treatment. None of the 16 injuries involved the main renal artery. Gelfoam was used for embolization of nine lesions and steel coils for four. Three others were treated with Gelfoam plus coils. Hemostasis was achieved in all and none required subsequent surgery. Renal tissue loss was small to moderate (less than 30%) in 12 patients and large (30-50%) in three patients. Transient postembolization hypertension occurred in one of the latter. We consider selective angiography/embolization to be an effective and safe means for diagnosing and treating wounds of the renal artery branches.