Epidural opioid analgesia has become an important therapeutic technique in the management of acute pain and has been demonstrated to be superior or equal to other parenteral opioid techniques (intramuscular, intravenous, PCA) with less associated sedation and significantly smaller doses of drugs. Beneficial therapeutic effects of epidural opioids as a result of improved analgesia include improvement in pulmonary function, modification of the endocrine-metabolic stress response, improvement in time to ambulation, decreased morbidity, and shorter hospital stay. The epidural administration of opioids is associated with potential side effects and complications, the most serious potential side effect being that of respiratory depression. This, as well as most of the other potential medication-related side effects associated with epidural opioid analgesia, is for the most part also associated with opioid analgesia provided by other routes of administration. These potential problems either occur rarely, or are controllable or preventable with appropriate patient selection and management. The potential benefits to the critical care patient as a result of the superior analgesia and reduced systemic effects associated with epidural opioid analgesia represent distinct medical and economic advantages, compared to conventional analgesic techniques.