The patient was an 84-year-old man. On July 1, 20XX, he experienced great difficulty in walking. On July 3, he suffered from serious complaints of backache and hyperhidrosis and was rushed off to a nearby hospital. A blood test was performed immediately. It showed that all the values conformed to DIC criteria. (?) A ultrasound scan revealed phiebothrombosis in the deep part of the legs. CT using a contrast medium found iliopsoas muscle abscess and periaortitis. The man was diagnosed with DIC, multiple organ failue, septic shock, and deep part phiebothrombosis. Treatment was done with an antimicrobial medicine and immunoglobulin preparations. In addition, an anticoagulant therapy was performed using DOA and heparin. Inflammation began to subside gradually but his fever did not abate. Contrast enhanced CT indicated abscess all over the body. After a 34-day stay in the hospital, he died. Although this case occurred in an urban area, MRSA was detected in the patient, suggesting that this strain is now one of the omnipresent bacteria. In this respect, this case was significant. Generally, a drainage procedure is taken for the treatment of iliopsoas muscle abscess. However, in this case, a remedial drainage was not used because the diameter of abscess was so small. As his temperature did not fall, a diagnostic drainage should have been used.