A 16-year-old male with autism underwent a preanesthetic examination under intravenous sedation before dental surgery under general anesthesia, because he had resisted all treatment.  To relieve the patient of physical and mental stress before he was brought to the operating room and venipuncture was performed for an intravenous drip, we administered midazolam to him orally.  The patient was in the habit of having coffee every morning using the same cup. Such adherence is characteristics of autismtic individuals. We, therefore, put midazolam in his morning cup. He drank it with good grace. As a result, he fell into a sedated state. We were thereafter able to smoothly bring on general anesthesia.  Our experience suggested that careful management allowing for disease characteristic could lead to the provision of hogh-quality medical services for mentally challenged patients.