The efficacy of ultrasonography was evaluated in radiotherapy for 32 patients with 82 metastatic bone tumor regions. Except for vertebral columns, ultrasonography was useful to detect metastatic bone tumors. Ultrasonography was applied to the radiotherapy planning in 21 regions, and was useful for the evaluation of radiotherapy effects in 22 regions. An appearance of "anechoic band" was useful for estimating tumor localization, and may be useful for the determination of the adequate dosage for palliative irradiation. Ultrasonography enable accurate localization of tumors such as sternal or costal metastases that are difficult by fluoroscopy. This means should be executed by radiotherapists.