Laryngoscopy and intubation cause an adrenergic response manifested by tachycardia and hypertension. Various phamacological agents have been administered prior to induction in an attempt to attenuate the adrenergic response but they all have limitations. The objective of our study was to determine if esmolol would be equally effective when adrninistered in a bolus with and without fentanyl. A double-blind, randomized trial was conducted in sixty ASA physical status 1 patients undergoing elective surgery. All patients were premedicated with 0.2 mg/kg diazepam orally and glycopyrrolate 0.04 mg/kg intramuseularyly 1 hour beforehand. Induction of anesthesia was accomplished with 4 mg/kg thiopental intravenously foUowed immediately by 0.15-0.2 mg/kg vecuronium and study drug (placebo, esmolol 150 mg, esmolol 150 mg and fentanyl 100 mcg). Endotracheal intubation was performed at 2 minutes after study drug adrninistration. Anesthesia was maintained with 1 MAC (±10%) isoflurane in 60% nitrous oxide in oxygen at a 5 L/min flow for 6 minutes. Heart rate and blood pressure were measured every minute by an automatic recording device. After laryngoscopy and intubation, maximum increase in stolic blood pressure above awake levels was 33 mmHg (p<0.05) and 14 mmHg (p<0.05) in esmolol 150 mg, esmolol 150 mg with fentanyl 100 mcg respectively, whereas systolic blood pressure increased 62 mmHg after tracheal intubation in patients with placebo. In six patients with esmolol 150 mg, rate-pressure product reached a level considered potentially dangerous to patients with coronary artery disease. However, when used with fentanyl, esmolol provides effectvie protection against the adrenergic response and increase of the rate-pressure product to laryngoscopy and intubation.