The diagnosis of aortic graft infection and aortoenteric fistula can be difficult to establish using conventional radiographic imaging modalities. Positron emission tomography (PET) imaging with 18-fluorodeoxyglucose (FDG) can rapidly provide anatomically clear images and define areas of inflammation with increased glucose metabolism. In this report the authors present a case of aortoenteric fistula diagnosed by FDG-PET. Early diagnosis led to rapid surgical intervention with graft removal and extraanatomic bypass. These encouraging results warrant larger controlled studies to evaluate the utility of FDG-PET in the diagnosis of prosthetic aortic graft infection.