Objective: To assess the use of sedatives, analgesics and neuromuscular blocking agents (NMBAs) in patients requiring mechanical ventilation in Danish Intensive Care Units (ICUs). Design: Questionnaires were mailed in December 1996 to all Departments of Anaesthesiology listed in the Annual Directory of Danish Hospitals. The questionnaires asked about the use of sedatives, analgesics and NMBAs in patients on mechanical ventilation in the ICU. Results: Forty-nine questionnaires were received from a possible 53 ICUs with ventilators (response rate 92.5 %). Sedatives and analgesics were given to patients on mechanical ventilation at virtually all the ICUs surveyed (60 % used the combination routinely). The frequency of use was influenced by both the level of ventilatory support and the type of underlying disease. Opioids, benzodiazepines and propofol were employed most commonly, in particular by continuous infusion. NMBAs were used in 65 % of the ICUs surveyed in less than 20 % of the total number of patients in the respective ICU. Overall 98 % of the ICUs reported the occurrence of some kind of side effect secondary to the sedative treatment, but in most ICUs they were reported to occur in less than 20 % of the patients. Conclusion: Sedatives and analgesics are widely used in patients requiring mechanical ventilation in Danish ICUs. NMBAs are only used in a few patients. The frequency of use is correlated to the level of ventilatory support required and to the kind of respiratory disease