The toxicity and efficacy of recombinant human granulocyte-macrophage colony-stimulating factor (rhuGM-CSF) is established in adults, but limited information is available on its use in children. The profound myelotoxicity induced by cisplatin (40 mg/m2 daily x 5) and etoposide (150 mg/m2 daily x 3) provides a model to test the clinical value of recombinant human granulocyte-macrophage colony-stimulating factor in pediatric cancer patients; myelosuppression occurred (absolute neutrophil count [ANC] < 500/microL) during 99 of 118 (84%) courses given to 44 children with refractory solid tumors. Fifty-nine courses (50%) resulted in hospitalizations for fever. Subsequently, rhuGM-CSF was added to this treatment regimen to: (i) determine the dose-limiting toxicity of this agent in children; and (ii) to determine whether it can decrease the duration and severity of neurtropenia and attendant complications. Here we summarize and update our experience with this glycoprotein in children with relapsed solid tumors.