Improved knowledge about the metastatic behavior of mucosal squamous cell cancer of the head and neck made it possible to reduce the extension of elective and even therapeutic neck dissections by sparing selected levels, thereby reducing morbidity. The diagnostic question of when to treat a clinically negative neck to avoid unnecessary overtreatment, even through selective neck dissections, might be answered with sentinel lymph node biopsy. A thorough and sophisticated evaluation of this technique is necessary when defining suited patients.