Rheumatoid arthritis (RA) is characterized by chronic joint inflammation and destruction. B cells play important role in modulating immune responses in RA. In the present study we assessed the impact of the B cell targeting as a third line treatment option. Forty-six patients with established erosive RA non-responding to combination treatment with DMARDs and TNF-alpha inhibitors were treated with anti-CD20 antibodies (rituximab). Rituximab was given intravenously once weekly on four occasions. All patients continued with the previous DMARD. Patients were followed by DAS28, levels of circulating B cells, frequency of immunoglobulin-producing cells, immunoglobulins, and rheumatoid factor levels during the period of 12-58 months. Clinical improvement was achieved in 34 of 46 patients (73%) supported by a significant reduction in DAS28 (from 6.04 to 4.64, P < 0.001). Infusion of rituximab resulted in the elimination of circulating B cells in all but one patient. Within 12 months follow-up, B cells returned to circulation in 86% of patients. Fifty-three percent of the patients were successfully retreated with rituximab or re-started with anti-TNF-alpha treatment. Of the 11 non-responders, five were retreated with anti-CD20 within 2 months, four of them with success, four patients received TNF-alpha inhibitors, the remaining two patients received an additional DMARD. Most of the RA patients resistant to TNF-alpha inhibitors may be effectively treated with anti-CD20 antibodies. The treatment is well tolerated and may be used repeatedly in the same patient and potentially increase sensitivity to previously inefficient treatment modalities.