90Y ibritumomab tiuxetan (Zevalin; Biogen Idec Inc, Cambridge, MA), the first radioimmunotherapeutic agent approved by the US Food and Drug Administration, is a promising treatment option in patients with relapsed or refractory low-grade, follicular, or transformed B-cell non-Hodgkin's lymphoma, including patients with rituximab-refractory follicular non-Hodgkin's lymphoma. The ibritumomab tiuxetan regimen is administered on an outpatient basis over approximately 1 week and with the simplicity of weight-based dosing (ie, calculation of whole body clearance is unnecessary). Other than acrylic shielding, only universal precautions are required to administer (90)Y ibritumomab tiuxetan, and patient isolation is unnecessary. This treatment regimen requires a coordinated multidisciplinary approach. Oncologists play a leading role in selecting patients for (90)Y ibritumomab tiuxetan therapy and in prescribing and overseeing the treatment.