Remifentanil has been available in Japan for 3 years. The use of this new opioid is considered a useful adjuvant to general anesthesia. Knowing the exact cost-effectiveness of remifentanil should lead to improved anesthetic outcomes with a reasonable cost. This single-blinded, prospective, randomized study compared the cost of remifentanil-based general anesthesia combined with isoflurane, sevoflurane, or propofol with fentanyl-based conventional techniques in 210 women who underwent breast surgeries. Remifentanil-based general anesthesia was no more expensive than fentanyl-based conventional anesthesia. Postoperative nausea and vomiting was significantly less frequent after remifentanil-based than fentanyl-based anesthesia. This study shows that remifentanil-based general anesthesia is no more expensive than conventional fentanyl-based anesthesia under the Japanese health care system because of the small difference in price between remifentanil and fentanyl.