We report on the 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) findings in a case of adrenocortical oncocytoma, a rare tumor of the adrenal gland with the literature review of other imaging findings including ultrasonography, computed tomography, and magnetic resonance imaging. To our knowledge, there have been no reports published in the English literature about 18F-FDG-PET findings in adrenocortical oncocytoma.