Therapeutic strategies for anaplastic carcinoma and malignant lymphoma of the thyroid are reviewed. Because of the rarity of both diseases among thyroid malignancies, the generally accepted treatment policy has not been established, although the importance of radiation therapy and chemotherapy has been well recognized for the treatment of both diseases. Hyperfractionated radiation therapy combined with suitable systemic chemotherapy will counter anaplastic thyroid carcinoma and prolong survival. Most patients with thyroid malignant lymphoma have better prognoses than anaplastic carcinoma patients. But delayed diagnosis and inadequate treatment still results in a poor prognosis, in spite of the more treatable characteristics of thyroid malignant lymphoma than anaplastic thyroid carcinoma. At present, early detection of the tumor and selection of a suitable therapy is necessary for the improvement of prognosis, and further clinical studies are required to establish effective regimens for multidisciplinary treatment.