One of the most common models of building a quality management system is the application of the requirements of the ISO 9001 standard. One of the requirements of the ISO 9001 standard in relation to the evaluation of measurable results is the implementation of internal audits. The goal of conducting internal audits is to determine the compliance of the quality management system with the requirements of the international standard HRN ENE ISO 9001:2015, and other system requirements defined by the organization itself. Internal audits are carried out as planned, and the auditing must include checking the requirements of all points of the standard. Internal audits in organizations are conducted not only to establish compliance with the requirements of the applicable standards, but also to improve the efficiency of all operational processes. During the implementation of internal audits of the system of the organization in question, it is very noticeable that internal audits are used as a "tool" for collecting suggestions for improvement, and for identifying risks and opportunities in the system. This is one of the very effective ways of collecting the above information and provides insight into the involvement of managers and other responsible persons at all levels of the organization. The subject of this Final Thesis is to determine the importance of conducting internal audits in organizations that have implemented a quality management system according to the HRN ENE ISO 9001:2015 standard, and to clarify what internal auditing actually is and what its purpose is. Internal auditing is a specific process that must be well planned and must include checking all points (requirements) of the standard.