Pain management in the critically ill patient presents a unique set of challenges for the intensivist. Once the patient has been assessed, stablized and a definitive treatment plan initiated, pain management may be incorporated into the global treatment plan. The benefits of analgesia appear to go beyond addressing humanitarian and ethical concerns. Pulmonary function is improved and pulmonary complications are less likely in patients with thoracic or upper abdominal injuries when pain is appropriately managed. Analgesia facilitates earlier mobilization and ambulation, which may decrease the incidence of deep venous thrombosis and pulmonary complications. The physiologic response to stress is blunted, with a resulting decrease in serum catecholamine concentrations, and normalization of cardiac output, oxygen consumption, and other markers of sympathetic nervous system hyperactivity. The catabolic state may be reduced, promoting positive nitrogen balance, better wound healing, and immune function. 22,23 Analgesic modalities available to intensivists include parenteral medications, epidural and intrathecal analgesia, interpleural analgesia, and peripheral nerve blockade. This article will focus on the use of intrathecal and epidural analgesia in the intensive care unit (ICU).