Introduction Type II endoleaks are a well-documented complication of endovascular aortic aneurysm repair. This case demonstrates the successful combined use of duplex ultrasound to assist in the percutaneous treatment of type II endoleaks. Case report A 75 year-old man who had previously undergone endovascular aortic aneurysm repair was found to have a type II endoleak. As the result of failure of the transfemoral endovascular coil embolization to repair the leak, the patient underwent computed tomography-and ultrasound-guided thrombin injection of the aneurysm sac via a trans-lumbar approach. Duplex ultrasound proved useful in guiding the placement of the translumbar needle, in confirming the thrombosis of the endoleak, and in demonstrating continued patency of the endograft. Conclusion The two imaging modalities worked in a complementary fashion to guide needle placement and to enable real-time imaging of color-enhanced flow within the aneurysm sac.