Since the founding of the Republic of Croatia until today, the production and supply of electricity has been in the domain of the Croatian Electric Power Company, stateowned enterprises, which had a monopoly in terms of electricity supply to both households and businesses. The quality of the service was not taken into consideration too much because the market was unquestionable. However, according to the rules of a free market economy, which by its Constitution guarantees the Republic of Croatia to all citizens, a fair market situation would be if citizens had the right to choose between several producers. Thus, at the beginning of this year, besides HEP, we can choose different foreign suppliers on the market, which offer lower cost electricity to HEP's distribution network. In order for HEP to d.d. retain its enviable market share and good goodwill in the minds of consumers, it has to introduce a system of full quality management, in all production facilities and at all levels of the organizational structure of its diversified network. Therefore, both thermal power plants and hydroelectric power plants within HEP are increasingly oriented towards improving the quality of products, but also the entire production process, by introducing the ISO 9001 standard. Initially, only partial quality control was carried out, which consisted of controlling and removing detected errors for future production processes . When it was perceived that such an approach does not guarantee the desired level of quality, the company turned to full quality control. It implies the involvement of all employees in the control system, the continuous control of production processes, and then the current removal of observed failures within the production process itself. Such an approach provides a significantly higher level of service quality with the aim that all production plants meet quality criteria and world standards.