OBJECTIVE: To quantify the prevalence and the impact of synchronous airway lesions identified by endoscopy in infants undergoing supraglottoplasty for severe laryngomalacia (LM). DESIGN: Retrospective study. SETTING: Tertiary care pediatric hospital. PATIENTS: Sixty patients who underwent supraglottoplasty for severe LM from 2002 to 2006. Patients who underwent preoperative tracheotomy, had previous airway surgery, or did not have 6 months of follow-up were excluded. Fifty-two patients met inclusion criteria. INTERVENTION: Supraglottoplasty (with carbon dioxide laser). MAIN OUTCOME MEASURES: Presence of synchronous airway lesions and their contribution to upper airway obstruction (UAO) and their effect on the postoperative course after supraglottoplasty. RESULTS: Fifty-eight percent of patients had synchronous airway lesions (SALs), of whom 77% had subglottic stenosis (SGS) and 47% had tracheomalacia, bronchomalacia, or both. Sixty-three percent of all patients required postoperative nonsurgical airway support. Eight patients had residual UAO requiring additional surgical intervention, with 3 revision supraglottoplasties and 7 tracheotomies performed. Infants with neurological conditions had a high rate of surgical intervention (55%; P = .001). Patients with SGS exceeding 35% but without any neurological condition had a prolonged hospital stay (>3.6 days; P = .02) and an 83% incidence (P = .04) of postoperative UAO requiring intubation. Infants with LM with laryngeal edema (LE) alone had increased frequency of postoperative nonsurgical airway support (P = .02) and a prolonged hospital stay of 1 day (P = .01) compared with infants without edema. CONCLUSIONS: There is a high incidence of SALs in patients undergoing supraglottoplasty. Neurological conditions, hypoplastic mandible, SGS greater than 35%, and preexisting LE independently adversely affected the postoperative course.