We report a case of a 59-year-old woman who presented with hypovolemic shock and compensated acidosis (preoperative arterial blood gases: pH 7.3, P(CO2) 31.9 mmHg, Pa(O2) 112.3 mmHg, base excess -9.8, Hb 6.4 g x dl(-1)) due to perforated descending colon, necessitating emergency surgery. Tracheal intubation had been performed preoperatively. Prior to induction of anesthesia, blood pressure was 106/74 mmHg, heart rate 119 beats x min(-1), and Sp(O2) 100% breathing room air. Anesthesia was induced with remifentanil influsion at a rate of 0.05 mg x kg(-1) x min(-1), sevoflurane 1% and rocuronium bromide 30mg, and was maintained with oxygen, air, remifentanil and sevoflurane. For a critical hypovolemia, in accordance to the guidelines for intraoperative critical hemorrhage and the Japanese practical guidelines for blood components therapy, we started to transfuse incompatible red cell (O+) since the identification of blood typing was suspended. The duration of surgery was 104 min, with an intraoperative total bleeding of 125 ml. Four units of total blood transfusion and 3,050 ml of infusion of Ringer's acetate solution were administered. The patient was transferred to ICU with tracheal intubation. No adverse reactions associated with blood type incompatibility were recognized.