Two siblings in whom respiratory symptoms developed immediately after birth subsequently were found to have bronchiectasis with strikingly similar distribution of lesions (mainly lower lobes). Inspiratory and expiratory bronchograms performed on one of the siblings demonstrated marked ballooning and collapse of proximal bronchi during tidal breathing. The clinical courses and roentgenographic findings, in the absence of other underlying abnormalities, suggest that the basic disease process was the absence of bronchial cartilage (Williams-Campbell syndrome). This would be the first reported familial occurrence of this syndrome. The familial pattern and the neonatal onset of symptoms support the theory of a congenital basis for this variety of bronchiectasis.