Abstract: Metastatic and recurrent pediatric solid tumors usually respond to chemotherapy but are likely to recur. Because of steep dose–response relationships, HDT requiring hematopoietic rescue may improve outcome. This strategy has recently been shown to be effective for metastatic neuroblastoma. Metastatic Ewing’s sarcoma appears to be a closely analogous situation, and promising phase II studies suggest that a definitive trial of efficacy would be appropriate. Phase I or II trials remain appropriate and are needed to define further the efficacy of HDT for most other poor prognosis pediatric solid tumors.