Diabetes and cancer are major global health issues. Cancer remained to be the first leading cause of death in Taiwan in 2016, whereas diabetes was ranked to be the fifth leading cause of death. Patients with diabetes are at a high risk of developing cancer, have a worse response to cancer chemotherapy and have a poor prognosis. It is very important to maintain blood glucose at nearly normal levels. While diabetic patients in terminal illness may have marked insulin resistance, frequent infections, anorexia, nausea and vomiting, strict blood glucose control may increase the risk of hypoglycemia. In palliative care, the symptoms should be treated rather than the blood glucose values. As treatment guidelines adjusted according to patient preference and the views of medical staff, each patient can receive the individualized treatment.