Every company has an appropriate adjusted organizational structure that enables it to achieve its objectives and generally run its business successfully. The entire organizational structure must be controlled in order for a company to function properly. There are different types and forms of internal controls, depending on the observed classification criteria. The internal controls can be defined as a set of methods, procedures, instruments or techniques that are incorporated into the organizational structure of a company. The governance structures of a company, primarily the executive management, designs internal controls in such a way that it can be determined whether the objectives of a company have been achieved. These objectives include to ensure reliable financial and non-financial reporting about company’s business, to comply overall company’s business with laws and other regulations, and to effectively and efficiently perform business operations, all of which together lead to the protection of company’s assets and the successful management of its operations. In the modern era, characterized by the post-pandemic period after the end of the respiratory disease COVID-19 pandemic, digitalization and related risks, for the governance structures of a company it is of utmost importance to design an effective and efficient system of internal controls in order to contribute to the achievement of set objectives and successful business. The COSO framework of the system of internal controls is one of the frameworks for designing, implementing and assessing of the company’s system of internal controls. Its objectives and components, supported by the principles and points of focus, give an initial frame and show a vision of how a system of internal controls should function in certain companies, including service companies, while taking into consideration their specifics. Service companies represent an important segment of the economy because their activity is essentially connecting production and sale. For service companies’ executive management to successfully manage their business, it is important to establish an appropriate system of internal controls and to continuously assess its effectiveness and efficiency, as well as to adjust the system to the changing modern business conditions. Thus, this final thesis presented the role and importance of internal controls for the successful management of service companies in the modern business conditions.