Purpose: Isolated limb perfusion with urokinase was used to salvage an acutely ischemic lower limb. Methods: Isolated limb perfusion with urokinase over a 90-minute period was used in the treatment of a 69-year-old female patient with acute ischemia of the left leg after thrombosis of a femoral artery bypass graft. Previous balloon embolectomy and heparin therapy had failed. The flow rate was able to be increased progressively without rise in the line pressure during the course of the perfusion, indicating an increase in capacity of the peripheral arterial bed. Fibrinogen and plasminogen levels in the isolated circulation remained low throughout the perfusion. The concentration of cross-linked fibrin degradation particles (d. dimer) rose progressively in the isolated circulation but remained at normal levels in the systemic circulation during perfusion. Results: Completion angiography demonstrated clearance of thrombus in the popliteal artery and appearance of arteries not seen on preperfusion films. Clinical improvement paralleled the angiographic appearances, with restoration of limb viability. Conclusion: We concluded that isolated limb perfusion with use of urokinase is safe and worthy of further investigation.