Small and middle-sized companies have an important role in the economy of every country, they are the initiator of employment, they develop national economies, encourage innovations and competitiveness more than large companies. They are important segment for industry. In Republic of Croatia, sector of small and middle-sized companies opens the greatest number of work places, encourages innovations and represents great importance for the growth and development of the economy. Percentage of small and middle-sized companies in Croatia, out of all registered companies is 99,7%. The obstacles that those companies face are mostly the ones of administrative nature, long-lasting procedures, inefficiency of the justice system, and the problem of difficult access to finances. Bibliography collected in purpose of writing this thesis, refers to the problems of small and middle-sized companies and their decision making process with financing. This thesis presents theories of the importance of small and middle-sized companies with obctacles that those companies face. The issue of this thesis refers to business decision making in small and middle-sized companies, different sorts of decision making styles and the process of making decisions about finances, financial needs of the companies, the goals of financial management, the tasks of financial managers, the role of managerial informational system in the decision making process, etc. This thesis describes the decision making process of financing small and middle-sized companies and other processes which follow the decision, from planning to control.