In order to compare tracheal intubation conditions, 34 adult patients about to undergo elective surgery received at random atracurium 0.5 mg X kg-1, pipecuronium 0.1 mg X kg-1 or vecuronium 0.1 mg X kg-1, intravenously. Intubation was attempted when only the first of the train-of-four finger contractions, arising from ulnar nerve stimulation, remained. The three relaxants provided effective conditions for intubation. The time required to suppress all but the first train-of-four response was shortest in the group given atracurium (P less than 0.05). Compound muscle action potentials (emg) were continuously filmed from just before induction of anesthesia until the trachea was intubated. The degree of neuromuscular blockade was similar in the three study groups.