Graduate thesis "The Risk of Collecting Claims in Micro, Small and Medium Enterprises" deals with issues related to the risk management of claims collection in business entities in Croatia and by analyzing the knowledge and use of indicators for managing it. Five major titles cover the theoretical part of the paper, which defines the concept of risk management, different types of risks, and the role of business and financial risks in business. It also explains the concept of claims and their type as well as the types of payment security instruments and how and when they are used. Particular emphasis is placed on the risk management of the collection of claims with the aim of improving the business and therefore explains the importance of the claims management system and the risk of billing, the importance of continuous monitoring of receivables, the importance of using a risk management model for claims collection and the problem of collecting receivables in companies with appropriate ways how to remove or reduce it. Furthermore, it describes the term and characteristics of small and medium enterprises and their importance for the entire economy. The last part of the paper deals with a survey of the impact of risk collection claims on businesses in Croatia that has shown that small business entities do not manage the risk of collecting claims as well as other business and financial risks. Nevertheless, research has shown that surveyed businesses have no problem with collecting or delaying their receivables, they realize the importance of managing the risk of collecting claims and are familiar with most indicators but do not have the resources (financial and human) and the ability for realization risk management collection of receivables.