A review of the patients seen at the Department of Obstetrics at Dokkyo University Hospital who had suffered placenta accreta/increta in the past 18 years, was performed. There were 10 such cases out of 9,716 deliveries during this period. This incidence is higher than that which has been reported in other Western countries. Forty percent of the patients in our study had placenta accreta/increta accompanied by placenta previa or low lying; 30% had had a prior cesarean section (C/S); 70% had previously experienced dilatation and curettage (D & C); 80% had previously undergone a C/S and/or D & C: and 40% had a history of miscarriage. Three of the ten patients with placenta accreta/increta required a hysterectomy; 2 patients were successfully treated with hemostatic stitches on the endometrium; and the remaining 5 mild cases were treated with removal of the placenta, either manually or with the use of forceps. There was no case of maternal death. In 2 cases, neonatal asphyxia was noted, but the neonate immediately recovered.