To define the optimal methods of diagnosis and repair of ureteral and renal pelvic injuries, we reviewed the records of 18 patients with 19 collecting system injuries (16 penetrating, three blunt). Hematuria was absent in five of 16 patients. Intravenous urography was diagnostic of ureteral injury in three and normal or nondiagnostic in eight. Retrograde pyelography was performed in only one patient and was diagnostic of bilateral ureteral injury. Treatment consisted of primary repair (minimal or no debridement and closure) in 11 injuries, ureteroureterostomy (debridement and reanastomosis) in six, ureteroneocystostomy in one, and transureteroureterostomy in one. Ureteral stents were placed in 12 injuries, nephrostomy catheter in one, and both in two. Four patients had no form of diversion. Followup was available for 14 patients; serum creatinine values were normal in each. Results of imaging studies in 13 were normal in 11; one showed mild caliectasis and one a resolving urinoma. Both intravenous urography and initial urinalysis may be unreliable indicators of ureteral and renal pelvic injury, and high suspicion mandates exploration. Usually the urinary tract can be satisfactorily reconstructed. Satisfactory urinary diversion can be achieved in most cases with an internal ureteral stent.