DIAMETER CHANGE of the larynx or trachea in normal individuals,1 or as a result of a congenital abnormality is not uncommon in infants.2,3 However, accompanying involvement of the bronchi is rare, and we are unaware of reports of bronchomalacia as an isolated abnormality in infancy. This paper reports an instance of isolated left bronchomalacia in a child without other known abnormalities of the tracheobronchial system. Report of a Case A 3-year old white boy, was the product of a normal pregnancy and delivery. The infant weighed 8 lb 6 oz (3,799 gm). A heart murmur was first noted at 6 weeks of age. His first episode of pneumonia occurred at 4 months and subsequently he has had at least seven documented episodes, all of which involved the left lung. At various times, Neisseria, γ- and αStreptococcus, and Hemophilus influenzae were cultured from the sputum. Skin tests for