Radioimmunotherapy (RIT) treatment for lymphoma is a novel targeted therapeutic approach. Several years of development of radioimmunotherapeutic compounds came to fruition in February of 2002 when (90)Y-ibritumomab tiuxetan (Zevalin, Y2B8) was approved in the USA and later in Europe, for the treatment of relapsed or refractory, low grade or transformed B-cell lymphoma. (90)Y-ibritumomab tiuxetan utilizes a monoclonal anti-CD20 antibody to deliver beta-emitting yttium-90 to the malignant B-cells. Clinical trials have demonstrated its efficacy, which is largely independent of the intrinsic activity of the anti-CD20 antibody. A similar anti-CD20 radiotherapeutic compound, (131)I-tositumomab, was subsequently approved in the USA. The advantages of increased efficacy compared to the naked antibody are gained at the expense of myelotoxicity which is dose limiting but reversible. Studies exploring expanded applications of radioimmunotherapy have been recently completed or are under way. It is hoped that RIT will be an ideal agent for consolidation after chemotherapy for both indolent and aggressive non-Hodgkin lymphoma as well as a useful addition to preparatory high dose regimens prior to transplant. RIT has been shown to be an effective and clinically relevant complementary therapeutic approach for patients with lymphoma.