Dexmedetomidine hydrochloride is a potent, highly selective alpha-2 adrenergic receptor agonist, broadly used as a sedative drug in intensive care units. We describe the case of a 59-yr-old patient who experienced drug fever caused by dexmedetomidine hydrochloride. The patient was transferred to the intensive care unit with an abdominal aortic aneurysm rupture. After initiation of sedation with dexmedetomidine hydrochloride, he developed pyrexia of more than 39 degrees C. This symptom improved rapidly 7 h after stopping dexmedetomidine hydrochloride. Other possible causes (such as infection) were sequentially eliminated.