The epidural injection of corticosteroid reduces the inflammatory process of the neural structure and its neighbor structures. Morphine, also injected epidurally, has been reported to alleviate severe pain with the short-acting property. In attempt to prolong the effectiveness of pain relief, we have studied the effect of the epidural injection of the morphine and steroid frorg May 1987 to Oct. 1987, and compared with the effect of the epidural injection of the steroid and local anesthetics from Jan. 1986 to Oct. 1987. In this study, we obtained following results; 1. The major causative diseases were herniated necleus pulposus in 34 cases(48.5%), spinal stenosis in 16 cases(22.9%) and spondylolisthesis in 9 cases(12.9%). 2. In morphine-injected group, 100% of acute group and 92.3% of chronic group was improved. In non-morphine injected group, there was no significant difference between the acute and chroinc groups. 3. The effect of epidural morphine and steroid was as follows; Complete relief 14 cases (63.6%), marked improvement 5 cases(22.7%), moderate improvement 2 cases(9.2%) and no relief 1 case(4.6%). The overall improvement was resulted in 21 cases(95.4%). 4. The effect of epidural steroid and local anesthetics was as follows; Complete relief 10 cases(20.8%), marked improvement 14 cases(29.2%), moderate improvement 12 cases(25%~ and no relief 12 cases(25%). The overall improvement was resulted in 36 cases(75%). 5. The average duration of pain relief was 2.5 months in morphine injected group and 1.3 months in non-morphine injected group. 6. The side effects associated with opiate, such as generalized pruritus, nausea, vomiting and urinary retention were reported in 16 cases(72.7%), but responded readily to Naloxone injection and subsided within 24 hours. It is considered that epidural injection of morphine and steroid prolong the effect and duration of pain relief for low back pain and sciatica when compared with the epidural injection of steroid and local anesthetics.