Stem cell transplantation (SCT) is an effective treatment for life-threatening hematologic and nonhematologic pediatric diseases. Reducing transplant-related mortality (TRM), a major complication of SCT, to improve long-term survival, therefore, is one of the main objectives of transplantation teams. We analyzed TRM and overall survival (OS) over the years in children undergoing SCT in our center. From June 1998 to October 2002, 156 consecutive children, 105 boys and 51 girls, median age 10 years (range, 2-18), with different diagnoses underwent SCT (100 autologous and 56 allogeneic). OS and TRM were analyzed in 2 different periods (June 1989-December 1998 and January 1999-October 2002) and grouped according to the different SCT modalities. The median follow-up was 18 months (range, 1-160). Autologous TRM showed a statistically significant improvement within 1999-2002 (0%) compared with 1989-1998 (12.2%) (P < .05). There were no statistical differences for allogeneic SCT. OS was 34% in the first period and 80.4% in the second period (P < .01), the improvement being for both autologous and allogeneic SCT. In our study, TRM decreased significantly for those children receiving autologous SCT in recent years. OS was significantly better in the latter period (1999-2002), both globally and for each SCT modality.