Investing is an integral part of entrepreneurial ventures and entrepreneurship in general, and an investment project means taking a set of actions that are necessary for the successful implementation of an investment project. In order for the investment project to be fully realized, it is necessary to cumulatively meet two factors, namely idea and capital. The strategic idea is realized through a strategic plan and it is necessary to set quality and realistic strategic goals that will be controlled at each stage of project implementation. Capital or sources of financing are an integral part of the financial plan, and the decision on financing is made by the manager. Sources of financing investment projects are different, and the paper analyzes own sources (savings and retained net profit), equity financing (business "angels", venture capital funds and public offering of securities), loan financing (commercial banks and lending incentives) and other sources financing (leasing, grants, strategic partnerships and public-private partnerships). Current sources of financing investment projects in the Republic of Croatia are subsidies for self-employment and European Union funds. The subject of the final paper is to analyze the sources of financing investment projects.