Ewing sarcoma (ES) is rare in Japanese people, and only 30-40 patients develop the disease annually. To diagnose ES, molecular techniques that aim to detect characteristic fusion genes are commonly used in combination with conventional histological and immunohistochemical examinations. The treatment strategy for ES is characterized by multi-disciplinary collaboration between pediatric oncologists, medical oncologists, radiation oncologists, and orthopedic surgeons. In recent years, numerous large-scale national or international multi-institutional studies of ES have been performed. Pre- and postoperative intensive systemic chemotherapy with multiple anticancer drugs is the standard treatment method for ES. Depending on the obtained surgical margin, postoperative radiation might also be performed. If preoperative radiological examinations indicate that surgical excision would be difficult, preoperative radiation can be administered. As the treatment outcomes of ES have improved, late complications and secondary malignancies have become a problem. After treatment, patients with ES require very long-term follow-up in order to detect secondary malignancies and growth-related musculoskeletal complications.