A case of cystic degeneration of the popliteal artery in a 58-year-old male is reported. Symptoms consisted of a claudication of abrupt onset and the correct diagnostic clue was initially given by magnetic resonance of the knee and confirmed by angiography. Treatment consisted of surgical removal of the cyst and saphenous vein angioplasty of the popliteal artery, with good anatomic and functional result at one year follow-up. Diagnostic tools and treatment of the condition are briefly discussed.