The first part of this thesis will focus on the origin and legal nature of the American Federal Reserve System established by the Federal Reserve Act of 1913 and Colombia's Bank of the Republic. Next, I will offer a deep study of the structure of the Federal Reserve System, concentrating on institutions like the Board of Governors, the Federal Reserve Bank, the Federal Open Market Committee, and member banks. The author also describes and analyzes Colombia's Bank of the Republic, placing emphasis on the reforms introduced by the new Constitution. In Chapter IV the main faculties, functions, and operations undertaken by each of these Central Banks will be briefly explained and described. The following chapter will focus on the role of central banks as supervisors and regulators of the financial system, particularly in the United States and Colombia. In this segment, this thesis will focus on other regulators and supervisors of the system and the areas in which the Central Bank of each country is empowered to regulate or supervise. Finally, this study will concentrate on all the arguments in favor of and against regulations and supervision of the financial system by the central banks and the similarities and differences of the American and Colombian systems in these areas.