Now that [18F] fluorodeoxyglucose positron emission tomography (FDG-PET) has become an established imaging tool in oncology, it is attracting interest in the field of infectious diseases. Several studies have used FDG-PET to examine the pathophysiology of HIV infection as well as other conditions such as lipodystrophic syndrome and HIV-related neurocognitive disorders. In clinical practice, FDG-PET has been proposed to assess fever of unknown origin or with lymphoproliferative disorders such as Castleman disease in individuals with HIV infection.