Critically ill patients often benefit from sedation to optimize their care and their ventilatory support. Ideally, incremental doses of a drug are administered to produce the desired level of sedation without toxicity or overdose. Because metabolism and elimination of drugs are often altered in critically ill patients, knowledge of the pharmacokinetics of sedative hypnotics is essential to ensure their appropriate selection and administration. Furthermore, the administration of sedatives via continuous infusion minimizes fluctuations in drug concentrations and permits more consistent control of the patient's agitation and anxiety. Physician preference and the patient's individual requirements and underlying diseases are the primary determinants for the selection of a given sedative. Benzodiazepines are the most commonly used sedatives in critical care. Midazolam is readily distinguished from other benzodiazepines because of its rapid onset and short duration of action, low incidence of thrombophlebitis and pain on injection, and minimal cardiovascular and respiratory effects. The physiochemical properties of midazolam allow for enhanced water solubility, which limits physicochemical incompatibilities. These properties make midazolam a valuable sedative that can be given via continuous intravenous infusion in the intensive care unit.