Real-time tissue elastography (elastography) is a new ultrasonography procedure that display tissue elasticity. We evaluated the usefulness of elastography in the diagnosis of cervical lymph node metastasis and its treatment results in patients with head and neck cancer. Metastatic lymph nodes tended to produce little distortion when displayed as hard tumors, and produced distortion, displayed as soft tumors, after radiation therapy and/or chemotherapy. Elastography thus is useful as a potential new diagnostic procedure in the diagnosis of neck lymph node metastasis in head and neck cancer.