The author attempts to conduct ethical evaluation of transplanting animal organs into human beings. She argues that such actions are inadvisable because they constitute an experiment on human being which usually leads to immediate death of the recipient. Moreover, costs connected with that type of practice are extremely high. The funds would be better spent on the development of other more promising methods of transplantology which do not bring such high risks connected with immunological reactions. Also, another risk connected with xenotransplantations would be excluded, namely the possibility of infecting human beings with animal diseases which are not serious in the case of animals but may be lethal to humans.