Several advances in imaging have become part of the work-up for localization, diagnosis, and management of infectious diseases and inflammatory disorders. Utility of multiple imaging modalities is a time-consuming step, and significant numbers of patients remain undiagnosed despite utilization of series of tests. Inflammatory cells have avidity for fluorine 18-labeled fluorodeoxyglucose ((18)F-FDG), and thus positron emission tomographic-computed tomographic (PET-CT) hybrid imaging provides anatomical and metabolic information that can be used to define the extent of infectious and inflammatory diseases and assess response to treatment. PET-CT provides a "one-stop test" in which use of hybrid imaging provides anatomical and metabolic information. The extent of disease is defined quickly, and response to treatment can be assessed. This modality also helps define the metastatic and/or septic foci where there is lack of localizing symptoms. More recently, there is increasing awareness among clinicians regarding the ability of PET-CT to help in diagnosing, characterizing, and assessing inflammatory disorders. This article reviews the usefulness of this imaging modality.