This paper aims to discuss the sequential use of rituximab and 90Yttrium-ibritumomab tiuxetan, a novel treatment approach in the management of refractory follicular non-Hodgkin's lymphoma. Radioimmunotherapy (RIT), which combines the benefits of targeted radiation therapy and monoclonal antibody, has significantly increased the response rate well in excess of 50%. This is explained by the inherent radiosensitive nature of lymphoma cells. We present a case of a 56-year-old male with refractory follicular lymphoma. The patient was referred for RIT, the first case in the Philippines. The patient was pretreated with two doses of rituximab followed by an intravenous infusion of 90Y-ibritumomab tiuxetan (Zevalin). Hematologic nadir was reached six weeks following administration of the radioimmunotherapy. During this time, the patient developed melena. Hematologic recovery was noted after three weeks. Re-evaluation with computed tomography three months after treatment showed significant reduction in the tumor bulk and resolution of lymphadenopathies. This report underscores the importance and evolving role of radioimmunotherapy in the management of refractory non-Hodgkin's lymphoma.