This study will compare the efficacy and safety of re-treatment with 2 doses of MabThera (rituximab) in patients with active rheumatoid arthritis (RA) who have previously experienced an inadequate response or intolerance to anti-tumor necrosis factor (anti-TNF) therapies etanercept, infliximab or adalimumab therapy. All patients will receive infusions of 1000 mg intravenous (IV) MabThera on Days 1 and 15; at Week 24 patients who have demonstrated a moderate or good response will be randomized to receive re-treatment with either 1 or 2 additional infusions of 1000 mg IV MabThera. The anticipated time on study treatment is 2+ years, and the target sample size is 100-500 individuals.