Bronchopulmonary dysplasia is a most frequent contemporary lesion of the lung in early childhood. It is characterized by clinical symptoms (neonatal respiratory distress syndrome) and by X-ray picture reflecting progressive morphological changes in the respiratory tract, i.e. in trachea, bronchi, bronchioles, and pulmonary acini, followed by interstitial pulmonary lesion. As usual, bronchopulmonary dysplasia is forerun by hyaline membranes and may be associated with or followed by interstitial emphysema. Pathogenetic participants are toxicity of highly concentrated and long administered oxygen, artificial mechanical ventilation with an intermittently positive pressure, barotrauma first of immature lung causing emphysema and pneumothorax and pneumomediastinum, lung edema, shortage of A and E vitamins and ceruloplasmin deficiency. Morphological changes in bronchopulmonary dysplasia are alike diffuse alveolar damage in bigger children or adults. Nevertheless, neonatal changes differ from later pulmonary lesion by evolving in an immature tissue and by being complicated with necrotizing "obstructive" bronchiolitis.