Persistent sciatic artery (PSA) is a very uncommon congenital malformation. Its incidence is estimated to be 0.01-0.06%. In this article, we have described the case of 59-year-old woman presenting with a left lower limb ischemia. She had a good pulse in her femoral artery. However, no pulsation of her left popliteal, pedal and posterior tibial artery was observed. The ankle brachial index (ABI) was 1.05 on the right side and 0.65 on the left side. Preoperative angiography and CT scan showed that persistent sciatic artery had been branched from left internal iliac artery and the distal side had completely occluded. This persistent sciatic artery had no aneurysmal changes. The left superficial femoral artery was hypoplastic. Blood supply to the left peroneal artery, anterior and posterior tibial arteries by collateral arteries was detected. The left leg ischemia was diagnosed due to chronic occlusion of the persistent sciatic artery. Then, the bypass grafting was performed from the left common femoral artery to the above-knee popliteal artery using an ipsilateral reversed great saphenous vein graft. Postoperatively, ABI improved to 0.89 on the left side.