The increasing incidence of non-Hodgkin's lymphoma (NHL), coupled with the lack of optimal treatment options, has prompted the development of novel treatments. Of these, radioimmunotherapy is one of the most promising. Two of the radiolabeled monoclonal antibody therapies being studied in the treatment of NHL are yttrium 90 (90Y) ibritumomab tiuxetan and iodine 131 (131I) tositumomab. The radionuclides 90Y and 131I emit beta radiation; 131I also emits gamma radiation, thus requiring more elaborate precautionary measures to limit radiation exposure. The monoclonal antibody portions of the drugs target the CD20 surface antigen that is present on the majority of B-cell lymphomas, resulting in direct radiation to the targeted cells, as well as indirect targeting of adjacent cells (known as the crossfire effect). Clinical trials of 90Y ibritumomab tiuxetan in patients with NHL have produced promising results. The safe and effective use of radioimmunotherapy requires a multidisciplinary team approach in which nurses play a central role.