A case of embryonal rhabdomyosarcoma (RMS) arising from adult lower proximal extremity is described. Rhabdomyosarcoma (RMS) is most common among children, but adult embryonal RMS is rare. The patient was a 44-year-old man with a large tumor of the left extremity invading to the pelvis. The histological diagnosis was embryonal RMS. Radiation therapy was delivered a total dose of 50 Gy to the tumor. Although adult RMS, usually pleomorphic type, is considered to be radioresistant, the tumor showed marked response to radiotherapy and local control was achieved easily in this case.