In September 2001, rituximab, a chimeric mouse-human anti-CD20 monoclonal antibody, was approved for the treatment of B-cell lymphoma by the Japanese government. Rituximab is the first monoclonal antibody that was approved for the treatment of malignant neoplasms by the U.S. Food and Drug Administration (FDA). Several clinical trials of rituximab conducted in USA, Europe and Japan revealed its promising therapeutic efficacy for B-cell lymphoma. Its minimal myelotoxicity allows rituximab to be combined with full doses of anticancer agents. Ongoing clinical trials will define the future role of rituximab in the treatment of B-cell lymphoma.