Background. Treatment with the radioimmunotherapy agent 90Y-ibritumomab tiuxetan (Zevalin®; Zev) has previously been shown to improve QOL in patients with relapsed/refractory indolent lymphoma, as measured by the validated Functional Assessment of Cancer Therapy-General (FACT-G) questionnaire (Wiseman et al. Blood 2000;96(11):734a, abstract 3173). Recently, a phase 3 randomized First-line Indolent Trial (FIT) was conducted to evaluate the use of Zev for consolidation of remission (complete or partial responses) following first-line induction chemotherapy in patients with newly diagnosed stage III or IV follicular lymphoma. Aims. Health-related QOL was evaluated as one of the secondary end points of the FIT study. All patients provided informed consent. Methods. Health-related QOL was measured using the EORTC QLQ-C30 (version 2), which specifically assesses QOL in patients with cancer and comprises 30 items grouped into the following dimensions: functional (physical, role, cognitive, social, emotional), symptomatic (nausea, pain, fatigue), global QOL, and other (dyspnea, difficulty sleeping, anorexia, constipation, diarrhea, perceived financial difficulties). The scores for the functional dimensions and global QOL range from 0-100, with higher scores denoting optimum level of functioning; scores for symptom-oriented dimensions also range from 0-100, with higher scores denoting greater severity in symptoms. The EuroQoL-5D (EQ-5D), which is not disease specific, was also used to assess health-related QOL. It includes both an assessment based on 5 dimensions (mobility, self-care, usual activity, pain/discomfort, and anxiety/depression) and a visual analogue scale (VAS) rating of overall state of health. The scores for the EQ-5D dimensions range from 0-1, with 1 representing an optimal state, and the scores for the VAS range from 0-100, with 100 representing the best health state. The questionnaires were administered at screening, week 14, every 6 months thereafter, and at the final follow-up visit. Descriptive statistics were used to compare scores between treatment groups. The change in scores from baseline was also assessed by gender, age, and first-line treatment. Mixed effects model was used to evaluate factors associated with the final VAS scores of the EQ-5D. Results. The mean EQ-5D scores at the screening and final visits were 0.83 and 0.84, respectively, for the Zev arm, and 0.84 and 0.83, respectively, for the control arm. The mean VAS scores at the screening and final visits were 77.52 and 77.64, respectively, for the Zev arm, and 76.57 and 78.60, respectively, for the control arm. An exploratory analysis of factors associated with final VAS scores showed that only the baseline VAS scores affected final VAS scores (p<0.0001). No treatment differences were observed in EORTC QLQ-C30 (all domains) scores across time points or changes from baseline. Results of subgroup analyses by baseline characteristics will be presented. Conclusions. In patients receiving consolidation therapy with Zev, health-related QOL parameters as measured by EORTC QLQ-C30 and EQ-5D questionnaires were similar to those of patients receiving no further treatment. Treatment with Zev consolidation is efficacious while maintaining QOL in patients with advanced-stage follicular lymphoma responsive to first-line induction treatment.