We have assessed tracheal intubating conditions in 60 ASA I or II children, aged 3-12 yr, after induction of anaesthesia with alfentanil 5, 10 or 15 micrograms kg-1, followed by an induction dose of propofol. Neuromuscular blocking agents were not given. Three aspects of intubating conditions were assessed on a four-point scale: ease of laryngoscopy, vocal cord position and degree of coughing on insertion of the tracheal tube. The number of patients in whom each component of the assessment was satisfactory increased significantly as the dose of alfentanil increased (ease of laryngoscopy P = 0.003; vocal cord position P = 0.0004; degree of coughing P = 0.018). Intubation was successful in 70%, 95% and 95% of patients after alfentanil 5, 10 or 15 micrograms kg-1, respectively, and conditions were considered to be excellent in 20%, 70% and 80% of patients, respectively. Side effects included pain on injection of propofol (27%), excitatory movements (5%) and bradycardia (1.7%).