Lung samples obtained from rabbits at prenatal period (19, 21, 23, 25, 27 and 29 days of gestation) and at postnatal period (1, 5, 10, 15, 20, 30 days following birth and adults) were used in this study. The tissue samples were examined by light and electron microscopy (EM).

Loose mesenchymal tissue was dominant at the 19^th day of gestation. Lung parenchyma resembled with a gland having branching buds. At the 21st day of gestation, an increase was observed in the branches and numbers of gland-like structures which were consisted of columnar epithelial cells. No fibres were seen in the connective tissue. At the 23^nd day of gestation, fibroblasts and smooth muscle cells around the developing bronchi were prominent. In the EM, the cytoplasm of type II,alveolar epithelial, cells were rich in organelles and glycogen particles were predominant. An increase was observed in the number of lung buds at the 25^th day of gestation. Simple prismatic epithelial cells transformed into cubical in shape. Collagen fibres became prominent. An increase was found in the number of fetal inclusions at the 27^th day of gestation. An increase in the number of alveoli with thin-wall were observed owing to the completion of central development of lungs at the 29^th day of gestation. Cilia formation also started at the same day.

At the first day of postnatal period, type I and II cells were present in the alveolar wall. In the silver stained sections, an increase in the thickness of collagen and elastic fibres was definite at the 5, 10, 15, 20 and 30^th days of postnatal period.