Internal audit plays a key role in international business, improving efficiency, transparency, and regulatory compliance. Its function includes evaluating and improving risk management, controls and processes, especially in complex international environments with different jurisdictions and cultural differences. Internal auditors help identify and mitigate risks associated with financial reporting and operational activities, ensuring compliance with local laws and international standards. In addition, internal audit contributes to resource management, fraud detection and optimization of operational efficiency. In a globalized business environment, auditors must understand different cultures and adapt their methodologies. Digitalization allows for faster and more detailed assessments. Also, internal audit assesses the sustainability and social responsibility of companies, which helps to preserve reputation and achieve long-term growth. The impact of internal audit on operating costs includes identifying and reducing risks, improving operational efficiency, regulatory compliance, fraud prevention, effective resource management, and supporting strategic planning. This not only reduces existing costs, but also prevents future costs through proactive risk management, ensuring long-term sustainability and profitability of the business. The subject of this paper is the impact of internal audit in international business on the company's operating costs. The first part of the paper refers to the theoretical part of auditing in international business and its impact on business costs, while the second part of the paper focuses on the selected company and the confirmation of the facts presented in the theoretical part of the paper. This research is based on primary and secondary data collected. The aim of this paper is to determine on the example of a company how internal audit in international business has affected the company's operating costs. Based on the information collected from the company, a conclusion is made about the impact of internal audit on business costs.