The research topic of this paper is internal accounting controls and their role in reliable financial reporting. The objectives of the paper are to explore what makes high-quality financial statements, to analyze the objectives of financial reporting and to analyze the importance of internal accounting controls in realization of reliable financial reporting. Since reliable financial reports contribute to the reputation and credibility of the company and provide users with the opportunity to make correct business decisions, reliable financial reporting must be one of the main goals of every company. Financial statements must provide useful information with all basic and enhancing qualitative characteristics, which relate to the financial position and financial result of the company and to cash flows in the reporting period. Regarding the risks of financial reporting, the task of company management is to design and implement mechanisms that enable a reasonable level of confidence in the reality and objectivity of financial reports. Internal controls are part of the internal control system, through which the management tries to achieve the company's goals. As a subtype of internal controls, internal accounting controls are responsible for providing a reasonable level of assurance about the reality and objectivity of financial statements and for safeguarding company assets. The design and implementation of all internal control systems is facilitated by the Integrated Framework of the COSO organization. Very common internal accounting controls are segregation of duties, authorization and approval controls, validation controls, access controls and physical controls, data controls, reconciliation controls, and supervisory controls. Internal controls must also be carried out over financial reporting, and as far as internal controls over financial reporting, it is possible to single out the division of duties, access control and making of trial balance. However, all internal controls have limitations arising from their nature, and it is extremely important to carry out supervision over them. The practical part of the work (Chapter 4) provides an insight into the implementation of internal accounting controls and internal controls over internal financial reporting in a company in the field of trade mediation, the owners of which are subject to Sarbanes-Oxley law, better known as SOX. By analyzing the mentioned control systems, the author evaluates their functioning and makes recommendations for improvement.