Atherosclerosis is the mechanistic basis of cardiovascular disorders manifested by damage to the walls of the aorta, coronary, cerebral and peripheral arteries, leading to the development of acute or chronic ischemia of internal organs and tissues. This publication describes a case of spontaneous atherosclerotic lesion of the aorta with the formation of a dissecting aneurysm in an African green monkey male. The ancestors were introduced from Ethiopia and Europe. The case monkey was housed as a family group in an outdoor enclosure with attached smaller room equipped with heating system. It lived 16.4 years. Pathological diagnosis was established through complete autopsy and histopathology. Main disease was chronic atrophic gastroenterocolitis in exacerbation complicated with alimentary dystrophy, cachexia (brown atrophy of the myocardium, liver, skeletal muscles). The concomitant diseases: complicated atherosclerosis of the aorta, dissecting abdominal aortic aneurysm with a large cylindrical organized thrombus in the aneurysm area, stenosing atherosclerosis of the renal arteries, vascular wrinkled left kidney; focal atherosclerosis of the coronary arteries and their branches with small foci of atherosclerotic cardiosclerosis and arteriosclerosis of cerebral arteries. The revealed changes indicate a significant similarity in the pathomorphogenesis of atherosclerotic lesions in African green monkey and humans. It allows us to consider this genus of primates as a promising laboratory model for studying the pathogenesis and mechanisms of regression as well as the effectiveness of therapeutic approaches to the treatment of atherosclerosis and its complications. © (2024), (Universidad del Zulia). All rights reserved.