Regulation and supervision is the main prerequisite for the stability of financial systems. Financial supervision consists of four elements: supervisory rules and regulations, supervisory structure, supervisory performance, and independence of supervisory institutions. The recent international financial crisis has made many countries to restructure the regulation and supervision architecture of their financial systems. Global benchmarks and best practices usher to three main controversies in the restructuring of the supervision architecture of financial systems: level of decentralization in the regulatory and supervisory system, macro and business prudential policy, and the supervisory realm of central banks. This paper analyses the characteristics, challenges, and weaknesses of financial system supervision in Iran and tries to propose a model to renew or improve the existing regulatory structure and the key reasons for monitoring various financial institutions and markets and important areas of prudential supervision and business, working within or outside the realm of Central Bank of the Islamic Republic of Iran. Finally, a combined-twin-peaks model is proposed for restructuring the supervision and regulatory architecture for the Iranian financial system.