Long-lasting remission after high-dose intravenous immunoglobulins in a case of relapsing thrombotic thrombocytopenic purpura (TTP) is reported. The patient had two early relapses after intensive plasma-exchange therapy. Serum platelet aggregating factor was absent. High-dose intravenous immunoglobulins (i.v. Ig) (0.4 g/Kg/day for 5 days) were infused. Platelet count promptly rose and 7 days after the completion of immunoglobulins complete response was obtained. The patient is still in complete remission, without further Ig infusion, 19 months later. This case adds to the anecdotal reports on the effectiveness of Ig, even when not associated with other treatments, in TTP. High-dose i.v. Ig could be successfully used in relapsing or unresponsive patients with TTP.