Cisatracurium is one of the ten stereoisomers contained in atracurium besylate. It has potent neuromuscular blocking property, no histamine release and organ independent elimination. This study was a prospective, double-blind, randomized comparison of the recommended intubating dose of cisatracurium (0.15 mg/kg) with vecuronium (0.1 mg/kg) to evaluate the efficacy and safety for endotracheal intubation. Sixty ASA physical status I or II patients, 15-55 yr. or age, 40-65 kg, scheduled for elective intermediate-duration surgical procedure were studied relaxant was given. Arterial blood pressure and heart rate were measured every minute. Onset and duration of relaxant were observed from train of four responses to nerve stimulator. The patient was intubating condition at 2 minutes after relaxant administration.In cisatracurium group, 63.3% of patients had good or excellent condition for intubation compared with 66.7% in vecuronnium group. Onset of action of cisatracurium and vecuroium were 3.4 ± 0.9 and 2.9 ± 0.8 min respectively. Duration of cisatracurium was 47.3 ± 8.3 min which was longer than 38.2 ± 9.7 min from vecuronium (p < 0.05). All of the patients had good recovery from muscle relaxant after reversal with neostigmine. There were 11 patients in cisatracurium group and 16 patients in vecuronium group who had bradycardia during study period. The cause might be induction with midazolam and fentanyl. One patient in cisatracurium group had erythematous rash. No bronchoconstriction of other significant adverse effect from both relaxant was found. So cisatracurium was safe and effective for intubation. Better condition might be achieved with higher dose or longer waiting time before intubation.