We present a case of infected abdominal aortic aneurysm due to salmonella enteritidis. F-18 FDG PET/CT was performed to diagnosis and during follow-up after antibiotic treatment. Computed tomography (CT) is considered to be the best diagnostic imaging modality in infected aortic lesions. In this case, a combination of CT and FDG PET/CT provided accurate information for the diagnosis of infected abdominal aortic aneurysm. Moreover, FDG PET/CT made an important contribution to monitoring disease activity during antibiotic treatment.