The clinical efficacy of rituximab, a chimeric monoclonal antibody targeted toward the B-cell specific antigen CD20, was initially demonstrated in cases of follicular lymphoma (FL), but the use of this antibody has been extended over the last few years to the majority of subtypes of B-cell CD20 positive non-Hodgkin's lymphomas, with promising results thus far. In MZL, small numbers of case reports have chronicled the use of rituximab as a single agent or phase II trial combination with chemotherapeutic regimens.