A 4-month old girl was diagnosed as having stage IV neuroblastoma of the right adrenal gland. Preoperative chemotherapy was given, followed by local surgical excision. Postoperatively, irradiation of the tumor bed and adjuvant chemotherapy was given for 11 months. Nine years after cessation of chemotherapy, the patient developed left hip-joint pain. Biopsy of the ischium showed chondroblastic osteosarcoma. Limb salvage surgery was performed after preoperative chemotherapy. Postoperatively, adjuvant chemotherapy was given for 14 months. Twenty-two months after treatment for the secondary osteosarcoma, the patient has been remained in disease-free condition without any evidence of relapse. A second osteosarcoma occurring outside the radiation field after treatment for neuroblastoma is quite rare. This unusual case emphasized the need for close monitoring for development of second malignant neoplasms in survivors of neuroblastoma even in the absence of a known predisposing factor, such as radiation therapy.