Patients with severe hypertension present the anesthesiologist with considerable difficulty. Without adequate treatment, serious problems may develop including myocardial ischemia or infarction, cerebral thrombosis or hemorrhage and renal damage during perioperative periods. However, drug interactions between antihypertensives and anesthetics may also be severe enough to produce synergistic bradycardia and hypotension. We have experienced managing a case with severe bradycardia and hypotension following halothane induction in a patient receiving beta-adrenergic blocker. This case illustrates the drug interaction between beta-adrenergic blocker and halothane.