Since intsaspinal morphine and demerol anesthesia have been reported we have noted anesthetic effects from the intraspinal nareotic injection. However, intraspinal mophine anesthesia appeared to cause prolonged respiratory depression with a slow onset and a very long duration which is not suitable for short surgical procedures. On the other hand, demerol or pentazocine were found to have a very short onset and duration with excellent local anesthetic effects. This study was primarily an attempt to take advantage of the rapid onset and short duration of demerol and pentazocine for simple and short surgical procedures. We had 43 cases scheduled for surgeries in the saddle ares i.e. hemorrhoidectomy, T.U.R., radium appli cator insertion and vaginal hysterectomy. All operations were performed under intraspinal demerol or pentazocine anesthesia, witch was satisfactory and the following results were obtained: 1) intraspinal dosage of demerol was 50mg or pentazocine was 30mg ofr hemorrhoidectomy, radium applicator insertion and T.U.R. For vaginal hysterectomy, the dosage was increased to 75mg~100mg for with demerol or 45mg with pentazocine. 2) Both analgesic effects apeeared from 1~2minutes after intraspinal injection and lasted 2 hours. 3) Mild somnolences were observed occasionally but no respiratory depression was seen. 4) Hemodynamics were stable throughout the entire procedures as well as postoperatively. 5) We came to the conclusion that a saddle block induced by intraspinal demerol or pentazocine injection was quite satisfactory in anesthesia practice for perineal surgery.