Pulmonary impairment in the offspring of smoking mothers is well documented by epidemiologic studies. The morphologic bases for the functional impairment are largely unexplored. We studied 17 infant lungs obtained at autopsy, ten from smoking (group 1) and seven from nonsmoking (group 2) mothers, by light (LM), transmission (TEM), and scanning electron microscopy (SEM). By LM, the alveolar mean linear intercept was similar in both groups; the total lung volume and alveolar surface area increased with the increase in gestational age in all lungs studied. By SEM, the sizes of the neuroepithelial bodies (NEB) were larger in group 1 than in group 2. By SEM and TEM, ciliated cells were increased, but the amount of dense core granules was decreased, in the NEB of the smoking group. Maternal smoking during pregnancy appears to alter the size and cellular composition of fetal NEB. The detailed mechanisms of the alteration in NEB and their implications are unclear from this study and needed further clarification.