BACKGROUND: Despite advances in treatment, the prognosis for patients with high-risk pediatric solid tumors remains dismal. Tandem autologous stem cell transplantation (ASCT) offers promise for improving outcomes in these patients. This study aimed to examine the efficacy and prognostic factors of tandem ASCT in pediatric patients with high-risk solid tumors. AIM: To determine the survival outcomes and prognostic factors in pediatric patients with high-risk solid tumors undergoing tandem ASCT. METHODS: A total of 40 pediatric patients with high-risk solid tumors treated from March 2015 to August 2022 were included in this retrospective study. The diagnoses of the patients included neuroblastoma, germ cell tumors, atypical teratoid/rhabdoid tumor, medulloblastoma, and pineoblastoma. After induction chemotherapy, all patients received tandem ASCT and were allocated into two groups (group A and group B) based on high-dose chemotherapy regimens. Prognostic relevance was evaluated by examining patient characteristics, such as sex, age, lactate dehydrogenase levels, primary site, the number of metastatic sites, and bone marrow involvement. RESULTS: The median follow-up duration since the first ASCT was 24 months (range: 1-91 months), with 5-year overall survival (OS) and event-free survival (EFS) rates of 73% and 70%, respectively, for the entire cohort. The 3-year OS rates were 67% for group A and 87% for group B ( CONCLUSION: Tandem ASCT demonstrates promising survival outcomes for patients with high-risk solid tumors, particularly neuroblastoma, with manageable toxicity and no transplant-related mortality.