Idiopathic thrombocytopenic purpura (ITP) is an autoimmune condition with detectable antibodies against several platelet surface antigens. The diagnostic criteria of ITP include isolated thrombocytopenia, normal bone marrow, and absence of other causes of thrombocytopenia. This condition is characterized by minor and serious bleeding complications, but it is rarely accompanied by thrombosis.1 We describe a patient with ITP that was not previously diagnosed, who developed cerebral infarction a few days after undergoing platelet transfusion and initiating steroid therapy.