Two cases of cutaneous necrosis occurred that were caused by intravenous administration of porcine heparin for deep venous thrombophlebitis. The lesions grossly resembled those of warfarin sodium-induced skin necrosis. However, histologically, no fibrin thrombi were noted in capillaries and vessels, a characteristic finding in warfarin necrosis. There was no evidence of vasculitis in the lesions. Both patients subsequently received warfarin without complications.