Dual cannulation was performed under ultrasound guidance for venovenous ECMO in this patient with severe ARDS. A multiperforated 25F drainage cannula (MEDTRONIC Biomedicus Multistage Venous Femoral 25Fr × 60 cm) was inserted via the left femoral vein, and its tip was positioned at the entrance of the right atrium as confirmed by transesophageal echocardiography. The return cannula was inserted through right jugular access. After 10 days of uneventful ECMO run, an abdominal CT scanner was performed to identify the source of recurrent sepsis. Surprisingly, the drainage cannula was positioned on the left side of the aorta (Fig. 1a). In this patient presenting a dual inferior vena cava (IVC), the drainage cannula entered the left iliac vein, continuing into the left IVC, the left renal vein and then the common part of the IVC just before entering the thorax (Fig. 1b, c).