BACKGROUND: Rituximab maintenance therapy was shown to significantly extend overall survival (OS) and progression-free survival (PFS) in relapsed/refractory follicular lymphoma (FL) in the pivotal EORTC 20981 trial. OBJECTIVE: To assess the long-term costs and cost effectiveness of rituximab maintenance therapy after induction therapy versus current standard practice (observation) from the French National Health Service perspective. METHODS: A lifetime transition model was developed comparing rituximab maintenance with observation. PFS and OS were obtained from the EORTC 20981 trial with a median follow-up of 28 months and extrapolated from 2-year Kaplan-Meier curves using a Weibull distribution. PFS and OS benefits of rituximab were conservatively assumed to last only 5 years. Utility data were obtained from a multicentre observational study using the EQ-5D questionnaire. Direct medical costs were obtained from French official sources. All costs are reported in euro, year 2006 values. RESULTS: The EORTC 20981 study demonstrated that rituximab maintenance was effective in the management of relapsed/refractory FL. The model results showed that life expectancy and QALYs were increased by 22% and 28%, respectively, in patients treated with rituximab. The incremental cost-effectiveness ratios (ICERs) were euro 7612 per life-year gained and euro 8729 per QALY gained. In a one-way sensitivity analysis, most of the ICERs fell within the range of euro 7000-12,000. The results tend to show that rituximab maintenance therapy may be a cost-effective strategy in the management of relapsed/refractory FL in France, with ICERs below those observed for other therapies in the oncology field. The cost of rituximab was partly offset by the lower cost of relapse due to a longer time in the disease-free health state for patients in the rituximab arm.