Popliteal artery aneurysms (PAAs) are rare in the general population, but are the most common peripheral aneurysms. PAAs are often bilateral and are associated with abdominal aortic aneurysms. They usually affect older men with established cardiovascular disease caused by atherosclerosis. Whenever they occur in younger men, other more unusual etiologies such as trauma, mycotic aneurysm, inflammatory arteritis or popliteal entrapment are responsible. The authors report a rare case of giant congenital PAA, revealed by acute limb ischemia in a 23-year-old patient. The evolution after resection of the popliteal aneurysm and end-to-end anastomosis with synthetic graft was favorable.