The inflammatory reaction is defined as the key regulatory atherosclerotic process. By comparing the type and volume of inflammatory cells in the abdominal aortic aneurysm (AAA) walls and the only atherosclerotic abdominal aorta abnormalities, the influence of inflammation on the formation of atherosclerotic plaque and the development of ATA was investigated. Comparison of the type and volume of inflammatory cells - macrophage, mast cell, lymphocyte B, plasma cells, auxiliary CD4 + lymphocytes T, cytotoxic CD8 + lymphocytes, in the AAA strain (40 patients treated with open surgical aneurysm repair) and rocks only atherosclerotic altered abdominal aorta (20 patients) T and regulatory CD4 + Foxp3 + lymphocytes T. Inflammatory cells are characterized by the representation of specific cellular markers by immunohistochemical method on paraffinic tissue cuts. The morphological characteristics of AAA (diameter, morphological type - fusiform / saccular, isolated abdominal aorta aneurysm or extended with one and / or two iliac arteries , presence of intraluminal thrombus), laboratory parameters (CRP, D-dimer, total cholesterol (age, gender, body weight, body weight, body mass index (ITM), smoking, blood pressure - systolic/diastolic, diabetes mellitus, presence of peripheral atherosclerosis, other peripheral aneurysms), and clinical risk factors of atherosclerosis, taking medicines - statins). In the AAA strains, a significantly higher number of cytotoxic CD8 + lymphocytes T, regulatory CD4 + Foxp3 + lymphocytes T and plasma cells were found in comparison to the only atherosclerotic abdominal aortic ventricular wall. Significantly larger number of auxiliary CD4 + lymphocytes T and macrophages were found in the abdominal aorta of the control group. In the largest number of patients, the diameter of AAA was 45-75 mm, aneurysms were more often sacrilege (32/40), isolated without the involvement of one and/or two iliac arteries with branches (36/40) and with intraluminal thrombosis (28/40). By comparison of the type and volume of the examined inflammatory cells in the AAA strain and the morphological characteristics of the AAA, a statistically significant higher incidence of lymphocyte B was found in the fusiform type of AAA. The type and frequency of the examined inflammatory cells are not related to other analyzed morphological characteristics of AAA. By comparing the type and volume of the investigated inflammatory cells with the investigated laboratory indicators and clinical factors of atherosclerosis risk, statistically significant results of plasma cell-related correlation with LDL and total cholesterol, cytotoxic CD8 + lymphocyte T and plasma cells were found with diastolic pressure values and regulatory CD4 + Foxp3 + lymphocytes with ITM and body weight of patients have no specific clinical relevance. By comparing the morphological characteristics of AAA with the investigated laboratory indicators and the clinical factors of atherosclerosis risk, the AAA diameter was significantly associated with elevated CRP values. The extended AAA type with the involvement of one and/or two lipid arteries with the ribs was statistically significantly more frequent in elderly patients. The higher incidence of cytotoxic CD8 + lymphocytes T in AAA is responsible for damage to smooth muscle cells and the destruction of the aortic wall. The inflammatory reaction in atherosclerotic alteration of the abdominal aorta was characterized by a higher incidence of auxiliary CD4 + lymphocytes T and macrophages important in the initial stage and stimulation of inflammation. An increased number of regulatory CD4 + Foxp3 + T lymphocytes and AAA plasma cells suggests overcoming the inhibitory inflammatory response in AAA. Different characteristics of the inflammatory response in the parts only atherosclerotic aortic and aorta scars indicate changes in the characteristics of the inflammatory reaction with atherosclerosis and the emergence of aneurysmatic complications. The fusiform type of AAA is characterized by an increased inhibitory inflammatory response of lymphocytes B. The type and frequency of the examined inflammatory cells are not related to other morphological characteristics of the AAA diameter, isolated or extended aneurysm with the involvement of one and / or two iliac arteries with the branches and the presence of intraluminal thrombus. The AAA diameter is statistically significantly associated with elevated CRP values, indicating the importance of inflammation in atherosclerosis progression and the development of aneurysmatic complications. The extended AAA type with the involvement of one and/or two iliac arteries with the bra nches is significantly more frequent in elderly patients, pointing to the aetiology of AAA in elderly patients.