PURPOSE The aim of this study was to evaluate the efficacy of fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) compared with bone scan in detecting bone metastases in patients with head and neck cancer. MATERIALS AND METHODS A total of 319 patients with head and neck cancer were identified in our database who had undergone F-FDG PET/CT, from January 2006 until June 2007. Of them 156 patients (age range 15-100 years) met our inclusion criteria - namely, biopsy-proven head and neck cancer, and bone scan and F-FDG PET/CT within 30 days. Comparison was made on a lesion-by-lesion analysis. MRI, multidetector CT, and the clinical course of the patients were our references. RESULTS F-FDG PET/CT identified (n=213) bone lesions in 18 patients, in addition to distant metastases in solid organs such as the liver and lung, lymphadenopathy above and below the diaphragm, and adrenal glands in 12 patients. However, bone scan identified (n=198) 16 patients. Bone scan missed two patients with confirmed bone metastases by means of biopsy in one patient and radiologically in the second. F-FDG PET/CT showed true-positive results in 18 patients, whereas bone scan showed true-positive results in 16 patients. F-FDG PET/CT showed true-negative results in 138 patients, whereas bone scan showed true-negative results in 134 patients. F-FDG PET/CT showed no false-positive or false-negative results. However, bone scan had two false-positive and two false-negative results. The overall sensitivity, specificity, and accuracy was 100% for F-FDG PET/CT and 88, 98, and 96%, respectively, for bone scan. CONCLUSION F-FDG PET/CT is superior to Tc-methylene diphosphonate bone scan in detecting bone metastases in head and neck cancer.