Alongside clinical investigation, imaging is an important diagnostic modality for guiding treatment decisions and particularly for surgical planning in head and neck cancer. The significance and type of imaging depends on localization of the primary tumor. Beside the primary tumor, each imaging procedure must also include the lymph nodes, in order to develop an overall concept of surgical treatment. In addition to the superficial growth of a tumor, it is of utmost importance that its infiltration also be detected by imaging, in order to define the extent of tumor resection and identify potentially necessary reconstructive procedures. The type of imaging needed to understand tumor localization and size, e.g., CT or MRI, depends on the region. In some cases the methods are complementary.