Infection of the sternum and anterior mediastinitis after open heart surgery are serious complications that are intractable with high case fatality rates. Frequently, infection spreads to an artificial foreign body in the mediastinum, causing difficulties with treatment. We report a case of infected pseudoaneurysm of the aorta at the anastomotic site of the artificial vascular graft. The infection spread from sternal osteomyelitis 9 years 5 months after aortic root replacement (Bentall procedure) for acute aortic dissection. We performed radical surgery that included en bloc resection of the infected sternum, pseudoaneurysm, and artificial vascular graft, with successful results. We report here the surgical strategy including the approach.