Management of patients with immune thrombocytopenia (ITP) refractory to standard treatment is difficult. Recent studies show that rituximab, a chimeric anti-CD20 monoclonal antibody, is useful in the treatment of ITP. We retrospectively studied 24 patients who received 29 rituximab treatments for relapsed or refractory ITP. Patients had received a median of 3 treatment regimens before (range 1-8) and 11 patients had prior splenectomy. Responses were achieved in 19 of 29 (66%) treatments. The median time to response was 3 weeks (range 1-20) from the start of therapy and median duration of response was 13 weeks (range 1 week-55 months). Responses were mostly short lived and after a median follow-up of 22 months (range 2-70), 10 (34%) responses were sustained after 6 months, 7 (24%) responses sustained after 1 year and only 5 patients continued to have a response at last visit after 8, 10, 24, 30 and 54 months of follow-up. Previous splenectomy was associated with a poor response (p=0.034). Patients who failed rituximab and had prior multiple treatments including splenectomy, had a poor outcome of further therapies. We conclude that rituximab is well tolerated and is useful in some patients with relapsed or refractory ITP; however, only about one-fifth of patients achieved sustained remissions. Patients refractory to rituximab had a poor response to further treatment.