The case reports of two children with obstructive lesions of the larynx are presented to illustrate the advantages of transtracheal ventilation for paediatric endoscopic laser surgery. The first patient was a four-month-old infant with inspiratory stridor due to a subglottic haemangioma obstructing 80 per cent of the lumen. The second patient was a five-year-old child with posterior synechiae of the larynx. The anaesthetic and ventilation techniques were the same for both cases. A transtracheal catheter was introduced percutaneously into the trachea under endoscopic control and connected to a high frequency jet ventilator. The advantages of this technique during laser surgery are: clear vision of the operative field, good gas exchange, elimination of airway trauma from intubation, reduction of the hazard of airway fires, and decreased risk of aspiration of blood and debris. In addition, this method of providing oxygen and/or mechanical ventilation may be extended into the postoperative period. In certain situations, this technique can be an attractive alternative to a tracheostomy with its potentially dangerous and incapacitating complications in infants and small children.