8 patients, 2 men and 6 women, 42 to 67 years of age, with bilateral multiple cysts of the renal sinus are described. 3/6 patients had macroscopic hematuria, pyelonephritis, 5/8 patients were with arterial hypertension and 4/8 patients were with renal failure. All patients were examine by ultrasound once more after a greater diuresis was achieved in order to differentiate from hydronephrosis. The isotopic nephrographic curves were normal in 2/8 patients and were disturbed in the remaining 6 patients. Hydronephrotic type curves were not found. Urography was performed to 4 of the patients and in 2 of them the diagnosis was polycystosis and in the other 2 patients it was bilateral parapelvic cysts. Possible mistakes in the diagnosis of bilateral parapelvic cysts are discussed. The reported cases with superimposed pyelonephritis and renal failure point to the need of prophylactic medical examinations of such patients.