The main aim of the article is to analyse the legal principles contained in the Constitution of the Republic of Poland of 1997, which constitute the basis for recognising the validity of pro futuro medical declarations. The issues raised are current because, along with the growing awareness of constitutional rights and freedoms and patients' rights in society, as well as demographic changes including the aging of humanity, the discourse on patient autonomy, expressed in self-determination about one's own treatment, is constantly raised in literature and doctrine. This issue is closely related to the pro futuro statement. Despite the lack of statutory regulations concerning the declaration in question, which has future consequences for the provision of health services, it can be assumed that the Constitution of the Republic of Poland provides a basis for recognizing the legally binding nature of such declarations of will.