This study will evaluate the efficacy and safety of MabThera/Rituxan plus methotrexate in patients with active rheumatoid arthritis who have had an inadequate response to at least 1 DMARD treatment. All patients will receive MabThera (1000mg iv infusion) on days 1 and 15, and methotrexate (10-25mg po) weekly. The anticipated time on study treatment is 3-12 months.