Four patients had pulmonary agenesis. All were symptomatic in infancy. In three, symptoms improved during two to six years of follow-up. One, who died at one month, had a unique combination of agenesis of the right upper and middle lobes and a hypoplastic right lower lobe supplied by systemic arteries from below the diaphragm, total anomalous pulmonary venous drainage to the left superior vena cava, tricuspid regurgitation with severe right atrial dilatation, patent ductus arteriosus, and reduplication of the right thumb. Abnormalities of the thumb were encountered in three patients. Parental consanguinity in all four patients suggests an autosomal recessive mode of inheritance. Cardiac catheterization and angiography are essential procedures for diagnosis and elucidation of the anatomic abnormalities and identification of associated cardiac defects.