Background. The use morphometric analysis to identify the characteristics of the respiratory system of the embryo with an overall cooling of pregnant female rats. Methods. The study was conducted on 60 pregnant adult rats aged 3-4 months, weighing 150-180 g with severely dated for all animals for a period of conception and the slaughter period, corresponding to the critical period of ontogenesis - the 14th day of gestation. The experimental group of animals was subjected to a general cooling of the 7th to the 14th day of gestation with a fence material on the 14th day. Histological sections of lung embryos were subjected to planimetric analysis. Results. The morphometric analysis of the “pseudo glandular” stage of development of light allowed to allocate two morphotype of organogenesis “compact” (I) and “air” (II). Total cooling of pregnant females brought to the restriction of modifications of the epithelial structures of fetal lung. Total area, outer perimeter, length, width tubular light, and the size of the lumen is substantially reduced, increased rows of epithelial formations are increased; organ stroma varies. Conclusions. Established embryonic lung parenchyma morphotypes allow ascertaining the existence of histogenetic options individually organogenesis of the respiratory system, and are implemented in the dynamics of their formation. Cold stress modifies the normal limits of the lung parenchyma, smoothing her morphotypes at a later embryonic period with stromal components.