The aim of this study is to determine if intra-bursal morphine and Bupivacaine mixed infusion provided useful analgesia after subacromial arthroscopic operation. At the end of the subacromial arthroscopy, continuous intra-bursal infusion catheter was inserted. In a double-blind randomized trial, Sixty patients were allocated to one of two groups: placebo group(n=30) received continuous saline infusion. Study group received mixed 5㎖ of 0.5% Bupivacaine, 2㎎ of morphine and 0.05㎖ of 1/1000 epinephrine as bolus and mixed solution of 40㎖ of 0.5% Bupivacaine and 8㎎ of morphine as maintenance dose with continuous infusion pump(0.5㎖ hourly). In the placebo group, two patients were discontinued due to leakage and catheter coming out each. Intensity of pain was evaluated preoperatively and postoperatively for 3 days by 10 graded visual analogue scale. Night pain, pain on motion, sleep disturbance, lying on painful shoulder and amounts of intramuscular pain killer were recorded. Analgesic effect for pain was cleared at 1st and 2nd postoperative day and there was less sleep disturbance for 3 days postoperatively in study group. There was no difference in pain on motion postoperatively. In study group, less pain killers were used in the first 48 hours postoperatively. The continuous intra-bursal infusion decreased perception of pain at resting stage and reduced supplemental analgesic requirement for 2 days postoperatively.