The following paper deals with the accounting treatment of non-profit organizations based on the example of a chosen association "Udruga Fokus". The aim of the paper is to provide a better understanding of accounting in the non-profit sector, considering the characteristics and role of the sector in today's society. The paper highlights some of the main characteristics of non-profit organizations and their sources of financing. The third chapter explains the accounting of non-profit organizations by examining the legal framework, accounting plan, accounting books and the need for monitoring financial activities through financial reporting. Furthermore, the main goal of the fourth chapter is to elaborate the accounting treatment of non-profit organizations and the specifics of their accounting, based on the example of Udruga Fokus. More specifically, it looks into their double-entry bookkeeping system, economic activity, assets and liabilities, audit insight and internal control systems, which include a self-assessment questionnaire and an action plan. The financial statements of Udruga Fokus are also analyzed. These include the balance sheet and income statement, as well as notes to the financial statements. The conclusion of the paper emphasizes the importance of conducting the accounting of non-profit organizations according to the rules of the profession together with the principles of transparency and responsible management, for the purpose of financial sustainability of non-profit organizations.