Thrombopoietin receptor agonists are used in addition to steroids for idiopathic thrombocytopenic purpura. A 55-year-old male with idiopathic thrombocytopenic purpura, treated with eltrombopag, developed a rapid decline in renal function following the increase in eltrombopag dose. Renal biopsy showed glomerular endothelial disorder and platelet thrombus, which suggested eltrombopag-induced renal-limited thrombotic microangiopathy. He was treated with steroids; however, his renal function did not improve, and hemodialysis was initiated. During the treatment, acute myocardial infarction and arteriovenous fistula obstruction occurred. After that, he was subsequently diagnosed with antiphospholipid antibody syndrome. Eltrombopag can cause thrombotic microangiopathy and, in some cases, result in renal failure. Patients with idiopathic thrombocytopenic purpura coexisted with antiphospholipid antibody syndrome are at increased risk of thrombosis with thrombopoietin agonists and require careful follow-up.