 This is a single-arm, single institution, phase II study of fludarabine monophosphate followed by Iodine I 131 Tositumomab for patients with previously untreated, advanced-stage stage III or IV low-grade, transformed low-grade and follicular non-Hodgkins lymphoma. The primary objective of the study will be to evaluate the safety of this treatment combination and the secondary endpoint will be to evaluate efficacy. 