Acquired subglottic stenosis is a common complication of endotracheal intubation in infants. The risk increases in trisomy 21, patients undergoing bypass surgery, and having gastroesophageal reflux disease. Less invasive endoscopic balloon dilatation of subglottic stenosis has become a more common treatment modality compared to open surgical technique. Airway-related surgery needs meticulous preparation and good communication between the anesthetist, surgeon, and staff. More precaution and more effective preparation and communication are needed in neonatal airway surgery as it is physiologically easier to desaturate and develop hypoxemia compared to adults. We report a case of successful balloon dilation of Myer-Cotton class III subglottic stenosis with intermittent supraglottic jet ventilation and bag-mask ventilation in infants with trisomy 21.