We report our results using once-daily intravenous (IV) busulfan (Bu)-based conditioning adjusted by weight without drug monitoring as myeloablative conditioning in 47 pediatric patients undergoing first autologous hematopoietic transplantation from 2006 to 2010. Median age was 4 years (range, 1 to 22 y). There were 35 boys and 12 girls. Conditioning was Bu-based in all patients. In medulloblastoma patients (n=12), IV thiotepa at 5 mg/kg/d×2 days was associated with Bu. In solid tumors other than medulloblastoma, IV melphalan was used at 140 mg/m/d×1 day. In lymphoma patients (n=9), IV cyclophosphamide was used at 60 mg/kg/d×2 days. Median number of CD34 cells infused was 4.65×10/kg (range, 1.7 to 58.7×10/kg). Median times to neutrophil and platelet recovery (>20×10/L) were 11 days (range, 8 to 16 d) and 12 days (range, 7 to 135 d), respectively. Median hospitalization time was 14 days (range, 9 to 92 d). Sixteen patients developed grades III and IV mucositis. Only 1 patient developed mild sinusoidal obstruction syndrome. No patient developed seizures or severe neurological complications. With a median follow-up of 18 months, probability of transplantation-related mortality and disease-free survival were 0% and 70%±8%, respectively. In conclusion, in our experience, once-daily IV Bu-based conditioning without drug monitoring for autologous hematopoietic transplantation in pediatric patients is a safe and effective regimen with no mortality.