Conventional scintigraphic imaging with (67)Ga citrate and in vitro labeled leukocytes is routinely used to evaluate infectious and inflammatory conditions. Recent studies suggest that positron emission tomography (PET) with [(18)F]fluorodeoxyglucose (FDG) also may be useful in this setting. Both (67)Ga citrate and [(18)F]FDG are highly sensitive tracers, but their specificity for detecting infection is lower than that of in vitro labeled leukocytes, which is the radionuclide gold standard for imaging most infections. PET has several advantages over conventional scintigraphic techniques, including higher spatial resolution and faster imaging times. In vitro [(18)F]FDG labeled leukocytes represent an initial attempt to develop an infection-specific, positron-emitting tracer. The experience to date with PET imaging of [(18)F]FDG labeled leukocytes is reviewed in this article.