The patient was a 60-year-old man who underwent distal gastrectomy for gastric cancer. The pathological diagnosis was Stage ⅡB. He received adjuvant chemotherapy(capecitabine plus oxaliplatin: CapeOX)for 6months and the postoperative course was uneventful. One year and 3 months after surgery, he visited the outpatient department for acute lower back pain. Blood tests showed elevated ALP(3,752 U/L), LDH(308 U/L), and CA19-9(69.4 U/mL)levels. Bone scintigraphy showed multiple bone metastases to the femora, ischium, iliac bone, vertebrae, sternum, costae, and scapulae in a super bone scan. The onset of disseminated intravascular coagulation(DIC)was observed later. The patient was diagnosed with disseminated carcinomatosis of the bone marrow. Radiation therapy was performed and anti-RANKL monoclonal antibody was administered for the bone metastases. Recombinant human soluble thrombomodulin was administered for DIC. He received chemotherapy( TS-1 plus cisplatin: SP)but died 4 months after the diagnosis. The prognosis of disseminated carcinomatosis of the bone marrow is extremely poor. We report this case along with a literature review.