Internal auditing is constantly developing and in today's modern world it is an almost indispensable part of organizational business. In this paper, a comparative analysis of the internal audit profession between the Republic of Croatia, the Federation of Bosnia and Herzegovina and the Republic of Srpska was studied with the aim of researching and understanding the similarities and differences of internal audit practices and the influence of different institutional, economic and regulatory frameworks on their development. The analysis indicated that there are certain differences in internal audit practices, although all three regions apply the International Standards for the Professional Practice of Internal Auditing (IPPF) and the International Standards on Auditing (ISA). The observed differences exist due to different political, economic and social factors of each of the mentioned regions. International standards form the basis for determining internal audit practices, ensuring a high level of transparency and compliance with global regulations. The Republic of Croatia has a detailed and strictly regulated legislative framework that enables a high level of supervision and control, while in BiH, due to the complex political and administrative structure, the regulation is more flexible and subject to variations within different regions. A big difference is made by the more stable economic conditions in Croatia, which enable greater investments in continuous professional training and advanced auditing practices. In Bosnia and Herzegovina, the economic challenges are more pronounced, and the profession of internal audit faces limitations such as less access to resources for professional development and challenges in harmonizing with international standards. The research also indicated that political and social factors influence the importance and role of internal audit in the mentioned regions. In Croatia, internal audit is characterized as a basis for improving corporate governance, while in Bosnia and Herzegovina, due to greater distrust in institutions, internal audit is perceived with reservations, which affects its effectiveness. Despite the challenges, there are significant opportunities for the further development of the internal audit profession in all three regions. The use of new technologies and increased specialization of auditors could further improve the efficiency of audit processes. Strengthening institutional capacities and international cooperation will be key to achieving a greater degree of compliance with global standards and improving the quality of audit services. A comparative analysis of the internal audit of the Republic of Croatia, the Federation of Bosnia and Herzegovina and the Republic of Srpska provided valuable insights into the common characteristics and specific challenges these regions face. It also provided an overview of the current state of the internal audit profession in the three regions, emphasizing the constant need for development and strengthening in order to ensure the highest possible level of transparency.