BACKGROUND: Midazolam, a water soluble benzodiazepine, is a good sedative, hypnotic, anxiolytic, and anticonvulsant drug. During stressful condition such as an operation, sympathetic tone increases and cardiovascular variables are unstable. This study evaluated the effects of midazolam for cardiovascular stability in elderly patients during anxiety and stress conditions. Method: Thirty patients (aged 61-93 yrs and in ASA 1, 2, and 3), who were scheduled for lower extremity surgery and showed elevated blood pressure before anesthesia, were divided into two groups. Group 1 (n = 15) has taken antihypertensive medication and group 2 (n = 15) had no hypertension history. Blood pressure and pulse of all patients were checked at 8 AM on operation day, arrival in operation room, 5, 10, 15 min. before anesthesia and every 5 min after anesthesia. Patients were given intravenous midazolam 0.01 mg/kg every 5 min until blood pressure lowered to 140/90 mmHg or spontaneous eye closing. RESULTS: The midazolam doses were 1.7 mg in group 1, 1.2 mg in group 2, and the total dose of midazolam for elderly patient was 1.5 mg (0.03 mg/kg). The sedation level was between the Ramsey scale 3-4. Age is a major determinant in deciding the dose of the drug. Blood pressure at arrival in the operation room was significantly elevated, but, 15 min after the midazolam injection, blood pressure was decreased to blood pressure level at 8 AM of the operation day. Conclusion: The total dose of midazolam for the elderly is nearly 1/3-1/4 of the recommened dose for healthy young adults. Small doses of midazolam in elderly patients were good for anxiolysis and cardiovascular stability.