Toxoplasmosis is a well-recognized life-threatening complication of hematopoietic cell transplantation (HCT). This report describes a pediatric patient with stage 4 neuroblastoma who developed cerebral toxoplasmosis after tandem high-dose chemotherapy with autologous HCT. Toxoplasmosis is rare in patients undergoing autologous HCT; however, tandem autologous HCT is more immunosuppressive than a single autologous HCT. Toxoplasmosis is a potential complication in autologous as well as allogeneic transplants, and should be considered in any post-HCT patient with neurological dysfunction. Rapid diagnosis and immediate antimicrobial treatment are crucial to avoid morbidity and mortality. Evaluation of toxoplasma serology should be standard in all patients undergoing tandem autologous HCT and seropositive patients should be started on appropriate prophylactic therapy.