Three children treated with bone marrow transplantation for acute lymphoblastic leukemia, Diamond-Blackfan anemia, and congenital amegakaryocytic thrombocytopenia developed secondary osteosarcoma in the left tibia at the age of 13, 13, and 9 years, respectively, at 51, 117, and 106 months after transplantation, respectively. Through treatment with chemotherapy and surgery, all 3 patients are alive without disease. We surveyed the literature and reviewed 10 cases of osteosarcoma after hematopoietic stem cell transplantation (SCT), including our 3 cases. Eight of the patients had received myeloablative total body irradiation before SCT. The mean interval from SCT to the onset of osteosarcoma was 6 years and 4 months, and the mean age at the onset of osteosarcoma was 14 years and 5 months. The primary site of the post-SCT osteosarcoma was the tibia in 6 of 10 cases, in contrast to de novo osteosarcoma, in which the most common site is the femur. At least 7 of the 10 patients are alive without disease. Osteosarcoma should be one of the items for surveillance in the follow-up of patients who undergo SCT.