The combination of intra-articular morphine and bupivacaine has been suggested as an ideal analgesic after arthroscopy. We performed a randomized double-blind controlled study in patients undergoing elective knee arthroscopy to investigate the analgesic effect of intra-articular morphine and bupivacaine. Sixty ASA physical status 1~2 patients were randomized into one of three treatment groups. All patients received general anesthesia with N2O, O2 and inhalational agents. The drugs were given by intra-articular injection by the surgeon before tourniquet release at the end of the operation. According to the mode of the drugs administered, the patients were divided into three groups; 1) Groupl (n=20) received 0.25% bupivacaine 2) Group2 (n=20) received morphine 1 mg in saline 3) Group3 (n=20) received morphine 1 mg in 0.25% bupivacaine. The injected volume was 25 ml, and all solutions contained 1:250,000 epinephrine. Additional postoperative analgesia was provided with intramuscular diclofenac sodium. The visual analogue pain scores in the recovery room(0.5 h) and 2, 4, 8, 12 and 24 h after surgery, time to first analgesic use, and total 24 h additional analgesic requirements were recorded. The results were as follows; 1) Visual analogue pain scores were lower in group 1 and 3 at 1~8 h. 2) Visual analogue pain scores were lower in group 2 and 3 at 24 h. 3) Additional analgesic requirements were lower for the first 12 h in group 1 and 3, but no difference was seen between groups over the 24 h study period. We conclude that, after elective knee arthroscopy, intra-articular morphine 1 mg in 0.25% bupivacaine 25 ml, with 1: 250,000 epinephine, may provide superior postoperative analgesia up to 24 h than bupivacaine or morphine alone.