Jehovah's Witnesses are one of the most informed groups of patients who know their rights and responsibilities of the medical personnel. In a situation when their right to self-determination in medical matters is violated, they often make use of opportunities to assert their rights in court. In this article the Author analyzes the legal provision related to physician responsibility for medical treatment performing without prior patient consent, and presents three types of responsibility that may be incurred by medical personnel for unlawful action - criminal, civil and disciplinary.