The best method to mobilize PBSCs in patients with non-Hodgkin's Lymphoma (NHL) is uncertain. We hypothesized that PBSC mobilization using an intensive chemotherapy regimen would improve outcomes after autologous hematopoietic stem cell transplantation (ASCT) in NHL patients at high risk for relapse. Fifty NHL patients were prospectively allocated to intense mobilization with high-dose etoposide plus either high-dose cytarabine or CY if they were 'high risk' for relapse, whereas 30 patients were allocated to nonintense mobilization with CY if they were 'standard risk' (all patients, +/-rituximab). All intensely mobilized patients were hospitalized compared with one-third of nonintensely mobilized patients. The EFS after ASCT was the same between the two groups, but overall survival (OS) was better for intensely mobilized patients (<0.01), including the diffuse large B-cell subgroup (P<0.04). We conclude that the intense mobilization of PBSCs in patients with NHL is more efficient than nonintense mobilization, but with greater toxicity. The equalization of EFS and superiority of OS in patients intensely mobilized to those nonintensely mobilized suggests that a treatment strategy using intensive chemotherapy for mobilization may be improving NHL outcomes after ASCT.