Nicotine, 1 mg/kg body weight/day, was injected subcutaneously in 3 female rabbits during gestational and lactating periods, and the lungs of the offspring were studied by scanning and transmission electron microscopy (SEM and TEM) on days 5, 10, and 25 postpartum. Three other female rabbits served as controls. The size and number of neuroepithelial bodies (NEB) as estimated by SEM were larger in the experimental group than in the control group, especially on days 5 and 25. Moreover, the NEB in the nicotine-exposed groups showed loss of normal boundaries and derangement of cells and granules by TEM. Neural components also became prominent. These findings suggest that chronic maternal exposure to nicotine may directly, or, through the neural route, indirectly induce hyperplasia and dysplasia of the NEB in the offspring of rabbits. Because NEB are suspected to regulate regional bronchial and vascular smooth muscle cells, such alterations may be similar to respiratory functional impairments found in infants of mothers who smoke.