The purpose of this research was to elucidate the main ethical issues that arise during decision-making and medical communication influenced by interfaith and intercultural differences. The statistical analysis of information retrieved from the United Nations official web site, as well as the analysis of secondary data taken from the literature sources, were applied to achieve the goal set. The outcomes of the study reveal that in Germany, Russia, and the United States, ethical problems in decision-making and communication in healthcare exist since the cultures and faiths of these countries' populations vary. Moreover, beliefs become more diverse due to the increasing number of migrants and medical tourists. It was found what ethical peculiarities of a particular religion can affect decision-making and communication during the provision of medical services to patients undergoing treatment in Germany, Russia, or the US. The results of the research can be applied in the scientific studies on ethical issues that arise in healthcare, as well as in the process of setting diagnosis, providing preventive care, treatment, transplantation, and euthanasia.