Through legislation and judicial decisions, the public administration (the city, first, and then the Empire) organized and regulated the activities of the various social groups. What was their impact on the complex world of banking and credit? After having briefly described how banking and financial life functioned in the Roman world, this chapter examines the way in which praetors and jurisconsults considered these activities, which legal rules they established, what were the effects of such rules, especially from the economic point of view, and how they developed from the first centuries of the Republic to the fourth century AD.