A clinical course of bilateral purulent pyelonephritis was analysed in 22 gravidas. The diagnosis of destructive renal lesions in gravidas is based on the findings of ultrasound investigation, chromocystoscopy, clinical and bacteriological examinations of renal urine obtained at separate catheterization of the ureters. Ultrasonic monitoring of the renal parenchyma is of key importance in specification of affection of each kidney. Treatment of gravidas with purulent lesion of both kidneys is combined, open operation being the main method. Two-stage surgery in renal carbuncles in the gravidas has some advantages. Surgical sanation of purulent foci and nephrostomy should be done first of all in the kidney with most severe alterations. Operation on the contralateral kidney is indicated after stabilization of the main clinico-laboratory indices and improvement of the gravida's health. The interval between kidney operations is 7-9 days, on the average. Bilateral nephrostomy resulted in a good pregnancy and delivary outcome in 17 cases. Removal of one of the affected kidneys after bilateral nephrostomy was indicated in 3 women. This stopped purulent intoxication and provided physiological delivary with normal fetus. The most severe clinical course of pyelonephritis and pregnancy was observed in 4 cases with purulent pyelonephritis of the solitary kidney. The other one was removed at nephrectomy. Preterm delivary occurred in 3 of these cases. One case was lethal. Thus, good outcome of therapy was achieved in 21 gravidas.