Imaging with fluor-18-deoxyglucose(FDG)-positron-emission tomography (PET) and CT combined in a single machine is a recent development. Using this technique both molecular and anatomical information are acquired. This results in an increased sensitivity and specificity in comparison to PET and CT as a single modality. One of the main advantages is that interpretation of PET images can be related to the anatomical information which helps to delineate the size and extent of a tumour as well as its relationship with surrounding tissues. It is also useful in planning surgical treatment and irradiation. At restaging PET-CT delineates the site and extent of a recurrence in the complex anatomy of the head and neck region and helps to define the location of a biopsy. This is particularly valuable in the anatomically complex head and neck region. Whole-body imaging can detect distant metastases and second primary tumours. PET-CT has the potential to become a part of the staging procedure of the primary tumour and also the follow-up in patients who have been treated for head and neck cancer.