OBJECTIVE: To determine the types and frequency of airway anomalies in patients with Pfeiffer syndrome. DESIGN: Retrospective case series. SETTING: Academic tertiary care pediatric hospital. PARTICIPANTS: Eleven patients with Pfeiffer syndrome, 6 of whom were severely affected, were identified. All were included in the study. MAIN OUTCOME MEASURES: Presence of tracheal anomalies, need for tracheotomy, and length of life. RESULTS: The 6 severely affected patients had mutations in genes that code for fibroblast growth factor receptor 2 (S351C [3 patients]; C342S [2 patients]; and W290C [1 patient]). Five of these patients were diagnosed during bronchoscopy or tracheotomy as having a congenital tracheal cartilaginous sleeve. In 1 patient, supportive care was withdrawn at 2 weeks of life, and the patient died. The remaining 5 patients required tracheotomy because of severe upper airway obstruction. Three of these patients died (at ages 9 months and 7 and 15 years). Two are still alive at ages 23 and 18 months. CONCLUSIONS: Patients with Pfeiffer syndrome manifest significant airway pathologic conditions. Upper airway obstruction is related to midface hypoplasia and secondary nasal obstruction. Tracheal anomalies have been infrequently reported.