84-year-old woman had been diagnosed hypothyroidism before, but she did not take tablets of thyroid hormone prescribed. Anorexia and decreased consciousness level were discovered by workers of the facility. Her family doctor found thyroid function abnormality as a cause, and she was introduced to our hospital to treat because the whole body condition was bad. Her physical examination was observed that JCS was 3-10. Laboratory examination showed that TSH 562.81 μIU/mL, fT4 0.40 ng/mL, pH 7.33, and Na 124 mEq/L. It was not a contradictory finding with the diagnostic criteria of mucus edema coma. Blood and peritoneal dialysis is denied, although her data indicated eGFR 8-10 ml/min/1.73 m2. Her hospitalization was long-term, but exhibited finally good clinical course. After three months of hospitalization, she was discharged from the hospital. The problems were as follows. The clear guideline of myxedema coma with end-stage renal failure state and many complications was not found. She and her family did not hope dialysis under this condition.We treated a case of myxedema coma in a case of an elderly person with terminal renal failure who did not hope dialysis. In addition to myxedema coma as a rare disease, there are many basic diseases in the elderly. Although it was a difficult case, it is important to repeatedly confirm the explanation and the intention of the person and the family with regard to the selection of the treatment policy.