Abstract
Abstract National audit systems play an important role in ensuring transparency and accountability in the use of public funds. European Union countries apply different approaches to the organisation and conduct of audits of public resources, which requires an analysis of their experience to identify best practices and possible areas for improvement. The purpose of this study is to identify the best practices in the field of auditing the effectiveness of the use of public funds aimed at infrastructure development, based on the experience of the European Union countries. The research methods include comparative analysis, classification by several criteria, study of the institutional structure, audit methodology, the degree of independence of audit bodies and the use of innovative technologies. The study highlights the importance of international cooperation to improve the quality of auditing and fight corruption. It is noted that despite the diversity of audit approaches in the European Union, there are common problems, such as professional development and the fight against corruption. Auditing plays a key role in ensuring the sustainability of infrastructure projects and improving public funds management. Evaluation of the effectiveness of the use of funds, in particular on the example of the Fehmarnbelt project, shows the possibility of significant budget savings and increased transparency. An important aspect of the study was also the identification of limitations and possible directions for further analysis, aiming to improve the effectiveness of audit practices and adapt them to changes in the financial and technological environment.