Although decreased bronchial cartilage is found in 50% of cases of congenital lobar emphysema (CLE), it can only be surmised that this defect produces a ball valve effect with consequent overinflation. We describe the flexible bronchoscopic features of CLE in a 3-year-old child. The observed airway patency during inspiration, and dynamic airway collapse on expiration suggests that bronchomalacia contributes to lung overinflation in these cases.