The main topic of this paper was to show theoretical and empirical analyzing possibilities of infrastructural investments of institutional investors, apropos insurance companies, pension funds and investment funds. The analysis included OECD countries, with special reference to the Republic of Croatia. With the theoretical part, the aim was to show infrastructure as a form of long-term investment that is a key factor for achieving achieve a development turnaround and ultimately sustainable economic growth. With the theoretical part, the aim was also to show institutional investors which through their business in the financial market allows portfolio diversification, improved corporate control, strengthening the deregulation process, exploiting technological development and increasing competitiveness. Subsequently, by empirically analyzing the data the aim was to show the proportions of institutional investors impact on the financial system with regard to the size of their assets and investment portfolios in which they invest their assets.With the empirical part, the aim was also to show the importance of long-term investment strategies and potential of infrastructure investments of institutional investors. With the empirical part, we also wanted to show the importance of long-term investment strategies of institutional investors and their potential for infrastructure investments. Based on the results of research, it is concluded that institutional investors, given the growing importance in financial systems and their existing long-term investment horizon of funds raised, which coincides with a longer period of investment in infrastructure, have a significant investment opportunity in infrastructure investment and through them they can contribute to the achievement of sustainable economic growth, both at the global level and at the level of the Republic of Croatia.