We report the case of a 4-year-old female with high-risk ALL in first CR who received a BMT from an 11-month-old matched sibling treated with G-CSF in order to obtain an adequate number of mononuclear cells in a limited volume of bone marrow. The absence of toxicity, efficacy of the procedure and quality of the post-transplant clinical outcome suggest such treatments are feasible and useful to overcome problems caused by donor age and/or body weight. In view of this experience we demonstrate how such an approach leads to a notable reduction in risks and in bone marrow donation costs.