We report the case of a 17 years old female with a Ewing's sarcoma of the left femur treated with limb sparing surgery followed by local radiotherapy of 45 Gy and adjuvant chemotherapy with vincristine, doxorubicine, cyclophosphamide, actinomycin D. The patient received neoadjuvant chemotherapy for osteosarcoma and a left femur resection with endoprosthesis replacement. The patient is alive and free of disease 4 years after the treatment of this second malignant neoplasm (SMN). This case shows that radioinduced SMN can occurr with relatively low doses of RT (<50 Gy) and that it may occur very late.