In bitches, multiple organ dysfunction syndrome involving kidneys may develop secondary to systemic inflammatory response syndrome that forms together with closed cervix pyometra. In the dog presented here, acute renal failure becouse of sepsis, leukocytosis, high BUN concentration, emesis and lethargy was diagnosed in postoperative period of ovariohysterectomy performed due to pyometra. The treatment applied for acute renal failure during 9 days postoperatively did not result in recovery and therefore, in day 10 peritoneal dialysis was carried out. After dialysis, creatinin concentration decreased to 3.1 mg/dL from 5.9 mg/d Land BUN concentration to 53 mg/dL from 121 mg/dL. Periton dialysis was ended after third application due patient’s general condition improved on day 12th. But the patient died on the day 13 and necropsy findings showed multiple organ dysfunction syndrome.