The problem stemming from the implementation of quality management system within enterprises is presented in this article. The quality of products is one of the most important criteria of enterprise’s performance. Thus, its improvement has significant impact on the growth of production efficiency and, therefore, economic growth. The functions of quality management system, such as quality planning, organizing work and encouraging employees to ensure product quality, monitoring and evaluating product quality and managing product quality, are discussed in this article. Ten groups of product quality indicators are distinguished according to its characteristics. It is identified that controlling is an essential function in the quality management process. The following controlling types facilitate the process of controlling: input control, ongoing control, operational control, acceptance control and inspection control. Nevertheless, the most effective method of quality assurance is the quality management system based on the international standards of the ISO 9000 series. Development of assessment indicators system for production performance and evaluation plays an important role in quality management. Based on the analysis of the indicators, it can be concluded that quality management is a coordinated management function related to the operation of the enterprise. Eight principles of quality management system are considered as well as factors which negatively influence the effectiveness and efficiency of the quality management system are identified in this article.