During the last years the relationship between financial development and economic growth has received widespread attention in the literature on growth and development. This paper summarises in its first part the results of this research, stressing the growth-enhancing effects of an increased interpersonal re-allocation of resources promoted by financial development. The second part of the paper seeks to identify the determinants of financial development based on Diamond's theory of financial intermediation as delegated monitoring. The analysis shows that the quality of corporate governance of banks is the key factor in financial system development. Accordingly, financial sector reforms in developing countries will only succeed if they strengthen the corporate governance of financial institutions. In this area, financial institution building has an important contribution to make. Paper presented at the First Annual Seminar on New Development Finance held at the Goethe University of Frankfurt, September 22 - October 3, 1997