In anesthetic induction of patients with severe aortic stenosis, maintenance of normal heart rate and blood pressure is critical. Remifentanil can blunt cardiovascular responses to tracheal intubation, but may cause circulatory collapse due to potent vasodilating effect. We studied retrospectively the optimal dose of remifentanil, which blunts cardiovascular responses to tracheal intubation and provides the hemodynamic stability to patients with severe aortic stenosis.