The Nellix endovascular aneurysm sealing system is a relatively new aortic endoprosthesis designed to overcome the problems associated with traditional methods of endovascular aneurysm repair. We report a case in which a 65-year-old male with abdominal pain was mistakenly diagnosed with an acute aortic dissection 7 days postoperatively after Nellix stent insertion, on the basis of the CT angiography findings. This report highlights the typical radiological appearances of the Nellix stent.