The topic of business ethics, which deals with the compatibility of ethical and economic requirements in economic institutions, has been one of the central areas of economic research in recent decades. However, although the importance of corporate responsibility has been registered both in research and in corporate practice, the causal relationships between corporate ethics and economic objectives, particularly those of marketing, are still largely unknown. The present dissertation analyzes the effect of external communication of ethical guidelines on customer loyalty. Using a theoretical analysis and an experimental study, the dissertation shows that communication of ethical guidelines leads to higher customer loyalty than non-communication, whereby the perceived value, brand image and customer gratitude act as mediating variables and explain the increase in customer loyalty. Furthermore, the skepticism about the credibility of ethical promises by companies functions as a moderator within the relationship model: The more skeptical a customer is, the less positive the communication of ethical guidelines will affect. Moreover, customer loyalty is increased to a greater extent by communicating ethical guidelines with male customers than with female customers.