Objective. To report successful treatment of a patient with venous ulcer related to acquired arteriovenous fistula. Material and methods. There was a 73-year-old female patient with primary varicose veins of the right lower limb (C2,3,4,6S, Ep, As,p, Pr2,3,18) and chronic venous ulcer without healing for previous 6 months. Results. We registered high-speed flow through incompetent medial calf perforator. Puncture of the perforating vein was followed by leakage of scarlet blood. Partial oxygen pressure (pO2) in perforating vein was similar to arterial parameters. CT angiography revealed contrast agent drainage from posterior tibial artery into enlarged veins. Considering anamnestic data and survey findings, arteriovenous fistula was suspected. We performed endovenous laser ablation of incompetent great saphenous vein and arterialized perforating vein. Varicose branches were removed by hooks or injected by 3% polidocanol foam. The ulcer healed within 2 months. Conclusion. Laser ablation of perforating vein should be considered in patients with severe venous insufficiency if perforating vein with high-speed characteristics of blood flow, pulsation symptom and high oxygenation are detected.