This study has been aimed at showing the influence of tobacco smoke, together with low protein diet on the lungs of newborn rats. The studied animals were Wistar rats. They were exposed to the tobacco smoke for 11 weeks (6 weeks before mating, 12 days during mating, and 21 days of pregnancy). Morphological analysis and interpretation of 48 one-day old rats was based on observation under the light and electron microscope. The study showed atelectasis of the lungs: the lung tissue was insufficiently extended, the alveoli were geometrically irregular and the alveolar septa were thick. Many extravasated erythrocytes and edema (latent as well as overt) were also present. The II type pneumocytes and their surfactant were poorly developed. Tobacco smoke caused the serious pathological effects and together with poor protein diet all changes worsened. For comparison, the lungs of control group were studied (lack of exposure to tobacco smoke); they were well aerated and their structure well-developed.