Facilitation of mechanical ventilation of the lungs using an infusion of vecuronium in 11 infants and children and four neonates in an intensive care unit is described. A loading dose of vecuronium of 0.1 mg.kg-1 was followed by an infusion at an initial rate of 0.1 mg.kg-1.hr-1. The infusion rate was adjusted to maintain a neuromuscular block of approximately 90% as assessed by the presence of one response to a train-of-four stimulation. The duration of the infusions varied from 9.5 to 179 hr. The mean dose of vecuronium administered was 0.14 mg.kg-1.hr-1 (+/- 0.05, SD) in the children and 0.11 mg.kg-1.hr-1 (+/- 0.05) in the neonates. Mean recovery times from the time of stopping the infusion until absence of apparent fade in response to tetanic stimulation were 51.7 (+/- 17.6) and 46.8 (+/- 16.5) min for the children and neonates respectively. No adverse cardiovascular or toxic effects were noted. This technique of vecuronium infusion to facilitate mechanical ventilation of the lungs is feasible and satisfactory in clinical use.