Extraneural relapses of medulloblastoma are associated with a very poor outcome. We present two cases of young adults who developed bone marrow metastases after treatment of medulloblastoma. A very good response to a sequentially scheduled combination of carboplatin and etoposide was observed. Then, high-dose chemotherapy was delivered consisting of busulfan and thiotepa followed by infusion of autologous hematopoietic stem cells. Toxicity of the conditioning regimen was acceptable. The patients remained free of disease 20 and 27 months from the time of relapse, respectively. Further studies are needed to evaluate the impact of high-dose chemotherapy in terms of survival of such patients.