Indolent non-Hodgkin's lymphomas (NHLs) comprise 35-40% of all adult NHLs. No standard curative therapy exists for these malignancies. Newer therapies, including monoclonal antibodies and radioimmunotherapy, have had notable activity in chemotherapy-resistant patients. 90Yttrium-ibritumomab tiuxetan is a radioimmunoconjugate approved by the Food and Drug Administration in February 2002 for the treatment of relapsed and refractory, low-grade, follicular or transformed NHL. Reported response rates are 67-80%, with a median remission duration of approximately 12 months. Toxicities are primarily neutropenia and thrombocytopenia, with few infectious complications. 90Yttrium-ibritumomab tiuxetan is an effective therapeutic alternative for the treatment of NHL.