This study retrospectively compared blood loss during sagittal split ramus osteotomy in patients receiving propofol-remifentanil (R group) and those receiving propofol-fentanyl (F group). All patients underwent sagittal split ramus osteotomy under general anesthesia during the 3-year 4-month period between October 2007 and February 2011 in an operating room at Tokyo Dental College Suidobashi Hospital. Blood loss in the R group was significantly less than that in the F group. Mean arterial pressure and heart rate, measured at 20 and 15 min after tracheal intubation, respectively, were both lower in the R group. No marked change was observed in blood pressure in the R group under general anesthesia, however. Volume of urine was also larger in the R group. The results of this study suggest that remifentanil is effective in reducing intraoperative blood loss during sagittal split ramus osteotomy.