Authors examined concentration of the leukocyte elastase (LE) in serum and walls of atherosclerotic abdominal aorta, ruptured and nonruptured aneurysms of abdominal aorta. Control group included LE level in normal abdominal aortas from multi organ donors. For trial 12589 PMN ELASTASE (2th Version) MERCK IMMUNOASSAY was using. From November of 1994 to December 1997 87 patients were explorated. Our study presents highest level of the LE in sequence: ruptured aneurysms, nonruptured aneurysms, atherosclerotic aortas and normal aortas. We did not confirm any statistic dependence between serum LE levels. Analysis between aneurysms diameter and their LE level, evaluated mutual dependence. Exploration proved connection between expansion and inflammatory genesis of atherosclerosis disease (activity of the PMN-elastasis in vessels wall).