The aim in this paper is to show greenfield and brownfield direct foreign investments and their impact on improving the economic growth and competitiveness by encouraging and developing the knowledge, technology and various sectors of the economy. Greenfield foreing direct investments presenting the investments in very new facility or activity. In order to have the characteristics of greenfield investments, companies must build entirely new facilities and plants in the target market on the agreed location in a foreign country. Usually there is a large capital investment. With the opening of the company's parent company is aware of the local, market, infrastructural and cultural opportunities of the country of residence. The parent company remains in full control of work being done, has its own know-how, based on which establishes performance. Brownfield foreing direct investments are purchasing existing buildings, facilities, warehouses and businesses. This form of investment is more characteristic in the transition countries due to lower investment risk and the existence of many, both unused and abandoned capacities. Most often dominate the industrial, military and railway complexes, coastal areas and facilities of public city services. The Republic of Croatia, as a country in transition, has used foreign investment in order to enhance the competitiveness of the domestic economy and the growth of total investment. The same growth it's expected in the future, despite the economic crisis has contributed to reducing the inflow of foreign investment. The increased growth is contributed by the fact that the Republic of Croatia is in the “leaders” countries group. In this group of countries, the activities should focus on the question of how to keep the competitive advantages that have initially made attractive for foreign investors.