Spinal opioids have dramatically influenced the way intractable pain of malignant origin is managed. To provide optimal pain relief, spinal opioids must be used in the context of a comprehensive cancer pain management treatment plan. The choice of epidural versus subarachnoid route of administration, as well as the specific opioids administered, require assessment of the individual needs of the patient. Factors likely to influence patient selection, including physiologic and behavioral abnormalities that may interfere with the patients' ability to assess pain relief, must be considered. During therapy, side effects must be anticipated and treated aggressively to assure patient comfort and safety. Although the chronic administration of opioids and other drugs into the epidural or subarachnoid space is in its infancy, advances in the pharmacology of spinal drugs and the development of new delivery system technology will probably expand the options available for the relief of cancer pain.