Monoclonal antibodies (MoAbs) have transformed the treatment of lymphomas. The first reports of studies using MoAbs appeared 8 years ago, and current therapy for lymphoma patients usually includes treatment with MoAbs once or several times during the course of their disease. This review covers the use of MoAbs in combination with chemotherapy for the treatment of patients with lymphoma. Rituximab, an unconjugated anti-CD20 chimeric antibody, is certainly the most widely used MoAb, but the use of other unconjugated or radiolabeled MoAbs is increasing quickly. MoAbs are effective if used alone, but the duration of effectiveness is limited. Therefore, when MoAbs are used in curative treatment, they are combined with chemotherapy. There are randomized studies demonstrating the benefit of adding MoAbs to the treatment regimen of patients with diffuse large B-cell lymphoma, but results of ongoing studies regarding the benefit in other lymphomas have not been reported. Many questions must be answered before the best setting for MoAbs in the treatment of lymphoma patients can be determined.