Follicular lymphoma and mantle cell lymphoma are incurable with standard chemotherapy regimens. One approach to improve outcome in patients with these diseases is high-dose therapy and autologous stem cell transplantation. Rituximab, an anti-CD20 monoclonal antibody, is specific for the B-cell surface antigen and can be used in autologous stem cell transplantation to eliminate lymphoma cells before the harvest (in vivo purging) or to prevent regrowth of malignant cells following transplant (post-transplant therapy). Preliminary data from an ongoing multicenter study evaluating the safety and efficacy of rituximab as a post-transplant consolidation therapy in patients with follicular lymphoma and mantle cell lymphoma are presented. After high-dose therapy and autologous stem cell transplantation together with rituximab treatment, 92% of patients are in complete remission at the 18-month study follow-up, suggesting that rituximab is a valuable and potentially curative treatment for patients with follicular lymphoma and mantle cell lymphoma. Six months after treatment, all evaluable patients became polymerase chain reaction-negative for the bcl-1 and bcl-2 chromosomal rearrangements and remained so during follow-up, indicating that rituximab is able to eliminate minimal residual disease and bring about high rates of durable remissions in these patients.