This paper emphasizes the importance of regional policy of the European Union as it's main investment tool. It's focus is the European Union's orientation towards investments into it's less developed regions. Also, it covers concrete solutions and goals to achieve equality between developed and less developed regions. Although the help is mostly directed towards less developed regions, it is said the European Union regional policy has a significant impact on all regions oft he Member States. Each region is faced with many difficulties, so the selection of possible solutions depends on a number of features, exactly which regional policy of the European Union seeks to ensure. The problems that the regional policy of the European Union is trying to solve can be related to different areas such as promoting economic growth and development, job creation, promotion of sustainable urban transport systems, reduction of environmental pollution and others. Depending on the region and the problems, appropriate solutions and financial resources are applied. As the European Union developed, so did the regional policy, the set of principles on which it was implemented as well as it's instruments and objectives. Croatia as European Union member also belongs to one of the regions that has the ability to strengthen it's position by using the Structural Funds and the Cohesion Fund. In Croatia, there are several critical areas that reflect many problems. Some of these problems are related to the investment in the transport network and environmental protection projects, job creation, improving life quality and the promotion of investment in research, development and innovation, Thus, the problems of each region including Croatia, can be solved by taking advantage of high-quality assistance that the European Union provides through the regional policy.