An 82-year-old woman presented with persistent left leg swelling despite 3 months anticoagulation for deep vein thrombosis. Ultrasound showed venous blood flowing back into the toe. Enhanced computed tomography scans and angiography showed occlusion of the left common iliac vein and a large number of arteriovenous fistulas. We made a diagnosis of May-Thurner syndrome coexisting with arteriovenous fistulas and we performed endovascular therapy only for the common iliac vein. We considered embolization for arteriovenous fistulas, but it seemed to be difficult to perform because of the possibility of development of collateral circulation and a large number of arteriovenous fistulas. After percutaneous balloon angioplasty, antegrade venous blood flow was restored, and stent implantation was not performed. After the procedure, swelling of the leg gradually reduced. She had no symptoms for the following 1 year.