One of the most debated issues today in the social sciences is the relationship between ethics and economics. Martin de Azpilcueta's (1492-1586) writings on morality hold a distinguished place in the theological literature of the early modern era because he addressed many of the fundamental moral issues surrounding the birth of market economics. This article evaluates the reception of Scholastic political economy in the history of economic thought and presents a detailed exposition of Azpilcueta's moral teaching on the commercial and financial practices of his day. The article concludes with a description of Azpilcueta's understanding of the intrinsic relationship between morality and economics, which, for him, was neither a mere juxtaposition nor an opposition of disciplines. Introduction