Although most often recognized in neonates and young children, congenital cystic adenomatoid malformation of the lung (CCAM) occasionally appears in later years. Three patients, aged 35, 24, and 7 years, are reported. Chest radiographs in each case suggested a localized patchy density, a cystic mass, or a multicystic mass, but computed tomography (CT) best demonstrated the cystic and solid components while ruling out bronchiectasis or major bronchial obstruction. Bronchography contributed no further diagnostic information compared with CT. Each patient underwent lobectomy. Histologically, the characteristic overgrowth of bronchiolar elements replacing normal parenchymal architecture was accompanied by some superimposed inflammatory change. Each patient had a history of pneumonia, and in such patients, characteristic radiographic features should suggest the possibility of late presentation of CCAM.