In this study, the patient-controlled analgesia (PCA) technique was used to compare the suitability of butorphanol with that of morphine in relieving postoperative pain. Twelve patients, 19-77 years old, who had abdominal surgery, used the PCA device through the first 24-hour postoperative period. Results showed that all patients expressed satisfaction with the PCA technique. Analysis of the degree of discomfort according to the verbal description scale, recordings of respiratory rate, and assessment of sedation status showed no significant differences between patients who received butorphanol and those who received morphine. Patients were able to maintain acceptable analgesia with minimal sedation. There were no adverse side effects reported with butorphanol.