Popliteal artery aneurysms are not so clinically frequent but are the most common peripheral aneurysms. They usually affect older men aged over 60 and are caused by atherosclerosis. Whenever they occur in younger men, other more unusual etiologies such as trauma, infection, inflammatory arteritis or popliteal entrapment are responsible. In this paper we present the case of a young male with an atherosclerotic popliteal artery aneurysm without a history of penetrating trauma or other possible etiologies.