The role of the elastolytic system arterial and venous tissues in pathogenesis of vascular pathology was investigated on rabbits and rats in experimental arterio-atherosclerosis. The obtained results indicate that elastase activity in aortic homogenates was significant higher in normal and pathological condition in rats than in rabbits. Elastase inhibitors (alpha 2-macroglobulin and alpha 1-proteinase inhibitor) also respond on angiosclerotic agent and level of alpha 2-macroglobulin increased significant in resistant animals (rats) but not in rabbits. In venous vessels determined more higher level of antielastase potential that may be explain its phenomenal resistance to different damage factors. The presented result confirm the importance of balance elastase and it inhibitors in pathogenesis of arterio-atherosclerosis.