Aim: To trace morphofunctional changes in the endocardium, arterial walls of various types, prostate gland, and adrenal gland during iodine deficiency in postnatal ontogenesis. Materials and Methods: The experiment involved 50 male Wistar rats (25 immature, aged 3-5 months, and 25 mature, aged 6-8 months). Group 1 (control) included 11 animals of both age groups, while Groups 2 and 3 (with iodine deficiency) consisted of 14 animals each, with material sampling on days 60 and 90 of the experiment, respectively. Morphological (light and electron microscopy), morphometric, biochemical studies, and statistical data processing were conducted. Results: The frequency of cardiovascular system damage, lesions of the prostate and adrenal glands, and iodine deficiency are important to study because of influence to the thyroid imbalance on these organs. The aim was to indicate the morphofunctional changes in the endocardium, wall of the arteries of various types, prostate gland, and adrenal glands in the dynamics of iodine deficiency during postnatal ontogenesis. Key components of thyroid signaling were found in the prostate gland, indicating a possible direct effect of thyroid hormones on this organ. Edematous changes in the epithelium of terminal secretory parts result from ischemia caused by edema in vascular walls and connective tissue elements of the prostate. Structural changes found in endocrine cells of the glomerular, fascicular, and reticular zones of the adrenal glands, along with the dynamic increase in cortical thickness during the experiment, suggest trophic disturbances, as edema was detected in vessel walls and stromal components. Thus, on both day 60 and day 90 of iodine deficiency, edematous changes occur in all organs in connective tissue components, wall of blood vessels, and epithelial tissues. Altered thyroid status triggers systemic interrelated changes in the organism. Conclusions: On both day 60 and day 90 of iodine deficiency, edematous changes occur in all organs in connective tissue components, wall of blood vessels, and epithelial tissues. Altered thyroid status triggers systemic interrelated changes in the organism.