Humanized monoclonal antibodies are dramatically improving the therapy of lymphomas. The anti-CD20 monoclonal antibody rituximab is active in follicular lymphoma, with an objective response rate varying from 48% to 73%, but also in others under subtypes of B lymphoma. The association of the antibody to CHOP (R-CHOP) chemotherapy increases in diffuse large cells lymphomas by approximately 15% complete remission rate (63% vs 76%) and survival. The rituximab allows to eliminate lymphoma cells of the bone marrow and it is integrated in the strategies of autograft. These monoclonal antibody can be coupled to radioactive product Iode131, Ytrium90, in view to deliver a more targeted radiotherapy. Remission rate is 70% with 30% of complete remission in follicular lymphomas. They have hematotoxicity and are more used as consolidation. Others monoclonal antibodies are under development and promise a great challenge for therapeutic studies in lymphomas.