Intravenous midazolam in doses of between 0.07 mg/kg and 0.1 mg/kg has been recommended for sedation in dentistry and some medical procedures and investigations. This study examined the variable sensitivity of patients to midazolam. One hundred and thirty-four fit but anxious patients between the ages of 16 and 63 years received midazolam intravenously for sedation for minor oral surgery. Doses required ranged from 0.04 to 0.40 mg/kg. Nineteen patients required doses less than 0.07 mg/kg; 59 patients required doses greater than 0.1 mg/kg. The mean dose per kilogram required for males was significantly less than for females. The wide variation in sensitivity to midazolam is confirmed.