BACKGROUND Whole-body F-18 FDG PET has been included in the 2014 Heart Rhythm Society guidelines for cardiac sarcoidosis evaluation to identify alternate sites of biopsy prior to endomyocardial biopsy. The purpose of this study was to evaluate the diagnostic yield of whole-body F-18 FDG PET/CT. METHODS All adult patients with suspected cardiac sarcoidosis undergoing same-day cardiac F-18 FDG PET/CT and whole-body F-18 FDG PET/CT between 10/1/2016 and 6/14/2021 to assess potential biopsy sites were retrospectively identified. Clinical indications, findings, recommendations, and outcomes were assessed. RESULTS Eighty-eight patients were included. Extracardiac PET findings suggestive of sarcoidosis were present in 30 patients (34%), 27 of which had thoracic findings (90%). Sarcoidosis was diagnosed in 11% of patients. Only 1% (1/88) was diagnosed by extrathoracic biopsy of a whole-body PET finding. Incidental findings were common (31%), resulting in 11 additional tests or interventions. Recommendations from extrathoracic findings affected treatment in one case: a drainage catheter placement into an unsuspected pelvic abscess. CONCLUSIONS Addition of whole-body F-18 FDG PET/CT to cardiac F-18 FDG PET/CT for the identification of extrathoracic sites of biopsy in patients with suspected cardiac sarcoidosis has marginal diagnostic yield but commonly results in incidental findings that rarely affect patient outcome.