These days, the epidural administration. of morphine is commonly used for postoperative pain re lief because even small amount of morphine (3mg) is enough to have an effect on specific opiates receptors of the spinal canal. We report a prospective double blind study of the efficacy of a single epidural dose of morphine on pain after spinal decompression. Postoperative pain was assessed by a linear analogue pain score and by the additional require ment for systemic analgesics. The results obtained are as follows:l. In spinal decompression, the adminitration of epidural morphine is easy, effective and safe because the epidural space has been already exposured during operation. 2. After operation the epidural route of morphine administration will give pain relief for up to 12 hours excellently. 3. When epidural morphine is given at the time of operations, the use of systemic analgesics is much reduced. 4. The side effects of epidural morphine are much reduced due to the small amount of morphine required. This simple procedure is recommended as an effective and safe method of reducing postoperative pain.