Postoperative pain relief and the side effects of epidurally injected morphine were investigated in 164 patients who received various types of operation including abdominal, genitourinary and lower extremities. Epidural morphine injection was given via an epidural catheter after operation. In 58% of total patients, pain relief was considered excellent, good in 30% and fair in 12%. The analgesia of each dose of epidural morphine lasted for 13 hours with everage. The side effects of epidural morphine were few and mild but urinary retention was in 9.8% of total patients, respiratory depression, pruritus, vomiting, catheter obstruction, catheter dislogement and bleeding through the catheter in one case respectively.