BACKGROUND: Elderly patients often have postoperative psychiatric disorders compared with young patients. METHODS: This study was undertaken to compare the effects of general or regional anesthesia on postoperative psychiatric disorders in 31 elderly patients with elective orthopedic and urological surgery. Mini Mental States Examinations(MMSE) was done to find out postoperative delirium at preoperative, postoperative 6hours, 1st, 3rd, and 7th days. RESULTS: Mean changes in MMSE score after general anesthesia were significantly decreased compared with preoperative score and with in regional anesthesia at postoperative 6 hours and 1st day. Postoperative MMSE scores were decreased below 17 points in 17 patients among 22 patients in general anesthesia and 3 patients among 26 patients in regional anesthesia. Hospital admission duration were significantly prolonged in general anesthesia compare with regional anesthesia. CONCLUSIONS: The incidence of postoperative delirium is more common after general aneshtesia than after regional anesthesia. Therefore regional anesthesia is recommeded in elderly patients to decrease postoperative delirium.