The aim of this study is to have a solid basis for the effectiveness of the 18F-FDG-PET/CT imaging technique, which has known advantages for patients with head and neck cancers during staging and restaging prior to treatment and to compare this method with the corresponding clinical and radiological methods.A total of 139 patients with squamous cell head and neck carcinoma underwent PET/CT imaging. A total of 146 PET/CT imaging was performed in all patients. PET/CT imaging performed for staging and restaging in 36 and 103 patients, respectively. At least one conventional imaging (CI) as CT and/or MRI was performed for each one of the total patients. PET/CT studies revealed 66 true positive, 72 true negative, 4 false positive and 4 false negative results whereas the same values for CI were 65, 64, 4 and 6, respectively.When all studies were analyzed on the basis of lesion for PET/CT, specificity was 94.7%, and sensitivity being 94.2%, where as corresponding values for conventional imaging methods were found 94.1% and 91.5% respectively. Recurrent lesions have been detected with PET/CT and treatment management was changed in 29 of 139 patients.FDG-PET/CT improves the diagnostic accuracy in head and neck cancer patients.