Refusal of blood transfusion due to religious belief such as with Jehovah's Witnesses, has brought about many clinical conflicts. To guarantee one's right of autonomy is important and so, in ordinary cases where patients themselves demand transfusionless treatment, physicians understand without much confusion and therefore, whether the doctors accept this request or not, can discuss the matter to the point. However, it may be difficult to resolve if the patient, who is not a believer, is unconscious and the patient's relatives request transfusionless treatment according to their own belief. We here show our own recently experienced case of a deep-coma due to acute cerebellar hemorrhage in a 67-year-old man, and consider the matters around his transfusion refusal and patient autonomy. We also discuss the recently released Japanese guideline for dealing with transfusion refusal cases due to religious reasons.