BACKGROUND: Radioimmunotherapy agents have a highly significant role in autologous stem cell transplantation as they improve tolerability and increase the efficacy of the conditioning regimen. METHODS: We retrospectively analyzed the efficacy and toxicity of yttrium-90 ibritumomab tiuxetan (Zevalin) combined with intravenous busulfan, cyclophosphamide, and etoposide (Z-BuCyE) compared with those of BuCyE alone followed by autologous stem cell transplantation in patients with relapsed or refractory B-cell non-Hodgkin lymphoma (NHL). The efficacy, toxicity, and engraftment characteristics were compared between 19 patients who received Z-BuCyE and 19 historical controls who received BuCyE. RESULTS: The 2 treatment groups shared similar baseline characteristics. The median time to platelet engraftment (>20x10(9)/L) and neutrophil engraftment (>0.5x10(9)/L) did not significantly differ between the Z-BuCyE group (12 days and 10 days, respectively) and the BuCyE group (12 days and 10 days, respectively). No significant differences were observed between the groups with respect to toxicities and treatment-related mortality. The median follow-up period was 30.4 months, and median event-free survival was generally better in the Z-BuCyE group (12.5 months) vs. the BuCyE group (6.2 months, P=0.236). No significant difference in overall survival between the groups was noted. CONCLUSION: Adding ibritumomab tiuxetan to BuCyE high-dose chemotherapy may benefit patients with relapsed or refractory B-cell NHL with no risk of additional toxicity.