The authors report a retrospective study of 34 cases of blunt renal trauma affecting a pathological kidney out of a total of 156 cases of renal trauma. The patients were between the ages of 3 and 60 years, with a male predominance (sex-ratio: 2.4). The predominant cause of trauma was a household accident, in 15 cases (44%). The clinical features were dominated by haematuria and pain. The underlying renal disease was dominated by renal stones (15 cases, 44%) and ureteropelvic junction (UPJ) abnormality (10 cases, 29%). Twelve patients with benign trauma and minimal underlying renal disease were treated conservatively. Surgery was indicated in the remaining 22 patients, but only 20 were actually operated. Nephrectomy was performed in 9 patients and partial nephrectomy was performed in 3 patients. Treatment consisted of UPJ plasty in 2 cases, uretero-caliceal anastomosis in one case, stone surgery in 4 cases and suture of ruptured renal pelvis in one case. The postoperative course was marked by the development of a urinary fistula in 1 patient, cured by drainage and deterioration of hydronephrosis in one patient. Lastly, one patient died from Wilms' tumour. This disease therefore tends to have a fairly benign course, which nevertheless depends on the underlying renal disease.