A 66-year-old woman with a history of endometrial cancer underwent a F-18 fluorodeoxyglucose positron emission tomography (FDG-PET). Abnormal uptake was noted in the right lower chest. CT scan showed a loop of colon interposed between the liver and the diaphragm, an entity known as the Chilaiditi sign. This case illustrates the importance to correlate abnormal PET findings with CT images. The Chilaiditi sign should be included in the differential diagnosis of lower chest uptake on an FDG-PET study.