Acute benzodiazepine and opioid withdrawal syndromes are increasingly described in intensive care unit patients. There is often some difficulty in distinguishing between the respective responsibilities of the sedative and analgesic agents. We report a case of acute benzodiazepine withdrawal delirium after a short course of flunitrazepam in an intensive care patient. Flunitrazepam was administered because of institution of mechanical ventilation. Recent data on the incidence and risk factors of the syndrome in intensive care unit patients are presented. Criteria for diagnosis and therapeutic guidelines are discussed.