BACKGROUND Duplicate inferior vena cava (IVC) accompanied by deep venous thrombosis is rare. The optimal treatment plan is determined according to the results of imaging, including venography. In this report, we present a case of successful treatment of a patient with duplicate IVC and deep venous thrombosis (DVT). CASE REPORT An 84-year-old man with history of hypertension was admitted to the hospital because of 4 days of moderate left lower-limb edema. A thorough examination led to the diagnosis of the DVT. The duplicate IVC was discovered during venography. As the blood from the left common iliac vein mainly flowed to the left IVC, and there were no other communicating branches before the convergence of the left and right IVCs, which was located above the 1st lumbar vertebrae body near the junction of the hepatic vein and the IVC, the strategy of placing only 1 filter in the left inferior vena cava were chosen, rather than placing 1 filter above the confluence of bilateral IVC, or placing a filter in each IVC below the level of renal veins on each side. Following that, the DVT was safely treated with thrombolysis and aspiration without the risk of pulmonary embolism. CONCLUSIONS This case report presented the complete evaluation and management of a patient with lower-limb DVT accompanied by the malformation of duplicate IVC. The filter placement strategy with duplicate IVC in the literature was summarized. We concluded that even in emergency situations, with comprehensive consideration, it is possible to perform endovascular intervention successfully and achieve satisfactory treatment results.