When a Jehovah's Witness patient rejects transfusion because of his religious doctrine, the anesthesiologist is required to make an important decision. Each doctor must approach his patient respecting the patient's wishes as much as possible, while still taking into account his own ethical criteria, moral judgement of the patient, and knowledge of medicine. This writer briefly examined the basis of the religious doctrine of a Jehovah's Witness advocate and consulted a scholar of the criminal court about the legal interpretation of the doctor's behavior in our present situation where no detailed judicial precedent was available. I summarized medical solution here by referring to foreign records of medical studies and case reports in the hopes that it may aid in anesthetic management of Jehovah's Witness patients.