Computed tomographic (CT) scans of 24 bronchopulmonary sequestrations in 23 patients were reviewed. Seventeen sequestrations were diagnosed at surgery, three at angiography, and four on the basis of radiographic or CT findings combined with appropriate history. Sixteen sequestrations were intralobar, and eight were extralobar; 21 were posterobasal. Seventeen occurred on the left side and seven on the right. Anomalous systemic arterial supply was demonstrated by CT in 16 sequestrations. In the others, a systemic artery was not shown, presumably because of unfavorable orientation or small size of the vessel. The lung abnormalities shown by CT were classified into three types: A = cysts containing air or fluid (n = 8), or soft-tissue masses (n = 2); B = emphysematous lung surrounding cysts, and/or soft-tissue nodules (n = 13); and C = lung hypervascularity (n = 2). In only three cases did the chest radiograph show the emphysematous lung tissue. Such emphysematous lung has rarely before been reported as a CT finding, and lung hypervascularity has not, to the authors' knowledge, been reported. The authors conclude that CT can be helpful in the diagnosis and evaluation of bronchopulmonary sequestration. Characteristic manifestations are (a) a complex lesion containing solid or fluid components combined with emphysematous lung or (b) any basal lesion supplied by a systemic artery.