The role of the elastolytic system in pathogenesis of vascular diseases was investigated on adult and one-month old rabbits in experimental ergocalciferol-induced media calcinosis depending on age aspect. The obtained results indicate that elastase activity was increased in aortic homogenates of one-month old rabbits but not in adult animals. The level of alpha 1-proteinase inhibitor is reduced in one-month old rabbits, and decrease of the alpha 2-macroglobulin content in arterial walls occurs in adults. A higher level of antielastase proteins in both groups of animals in venous vessels is determined. After effect of ergocalciferol in the veins of one-month-old rabbits, differs from the adults, a significant increase of the inhibitor content is observed. The presented results confirm the importance of balance between elastase and it inhibitors in pathogenesis of arteriosclerosis.