We studied 429 cases (3 bilateral) of renal injuries in 426 patients diagnosed and treated at our service from 1965 to 1990. Four-hundred twenty (98.59%) were blunt and 6 (1.41%) were penetrating injuries. In 313 the renal lesions were grade I (72.96%), 69 grade II (16.08%), 27 grade III (6.29%) and 20 were traumatic injuries to pathologic kidney (4.66%). Surgery was performed immediately in 67 cases (15.61%) (35 grade II, 21 grade III, and 11 previously pathological kidneys). Surgery was delayed in 34 cases (7.92%) (1 grade I, 23 grade II, 5 grade III and 5 pathological kidneys). Three-hundred twenty-eight cases (76.45%) were managed conservatively (312 grade I, 11 grade II, 1 grade III and 4 cases of traumatic injury to previously pathological kidney). Preservation of the renal unit was achieved in 100% of those with grade I lesions and in 91.17% of those with grade II that had been treated conservatively or submitted to delayed surgery. Of the grade II lesions that were immediately treated, 22.58% required a nephrectomy procedure. Of the grade III lesions and the cases of traumatic injury to previously pathological kidney, nephrectomy was required in 72% and 65%, respectively, although delayed surgery permitted more precise indication in a hemodynamically stable patient. The mortality rate in our series was 1.87 (8/426).