A woman in her 60s was referred to our department with advanced rectal cancer and multiple unresectable metastases of the liver and peritoneum. She had been diagnosed with idiopathic thrombocytopenic purpura (ITP) in her 20s, with a platelet count maintained at approximately 1.0×10(4)/μL by prednisolone; on admission, her platelet count was 0.9×10(4)/μL. Romiplostim, a thrombopoietin receptor agonist, was administered prior to chemotherapy. Her platelet count increased to approximately 10.0×10(4)/μL during chemotherapy with oxaliplatin plus capecitabine, and she developed deep venous thrombosis requiring inferior vena cava filter placement and anticoagulation. No other severe adverse events occurred. There is no standard regimen for the treatment of solid tumors in patients with ITP. This is the first reported case of the concomitant use of romiplostim and chemotherapy for advanced rectal cancer. We believe that romiplostim can effectively salvage the platelet count in emergency situations such as during chemotherapy.