The popliteal artery is the main site of occurrence of peripheral aneurysms. Acute presentations constitute a potential threat to limb viability and to life, especially in the event of rupture. Rupture is a rare event, but one that demands an immediate intervention decision to achieve a satisfactory treatment outcome. The gold standard treatment is conventional surgery, effecting repair by interposition of a great saphenous vein graft. Studies conducted in recent decades have found associations between Marfan Syndrome and peripheral aneurysms. This report presents a case of a ruptured left popliteal artery aneurysm successfully treated in an 82-year-old patient clinically diagnosed with previously unknown Marfan syndrome.