Remifentanil is an opioid with a unique pharmacokinetic profile. Its metabolism by nonspecific esterases results in rapid and uniform clearance leading to highly predictable onset and offset of action. This review will describe the features that set remifentanil apart from other opioids and outline its potential usefulness in a critical care setting. Most studies on remifentanil have been in postoperative neurosurgical and cardiothoracic ICU settings. In the former, the agent has proved especially useful because rapid predictable emergence from sedation allows regular clinical evaluation. Remifentanil also prevents procedure-associated rise in intracranial pressure. In the cardiac setting, the drug provides excellent intraoperative hemodynamic control while allowing return of spontaneous ventilation within minutes of discontinuation of the infusion. One study suggests that the use of remifentanil will reduce the need for postoperative intensive care, especially after hepatic transplantation.