Topicality. Our time is characterized by rapid growth in the number and quality of various computer systems. An increasing number of users, both in their daily and professional activities, need data transmission and Internet access services in addition to traditional communication services. The network infrastructure created as a result of convergence should provide the needs of preferably all service users. But in order to ensure the necessary quality of service, it is necessary not only to have information about the state of the telecommunications network, but also to be able to forecast it. This fact requires improving the analysis of quality indicators characterizing the state of the telecommunications network. The purpose of this work is to develop a method of analyzing quality indicators of a computer network of a critical application information system. The object of the research is the process of functioning of the computer network of the information system of critical application. The subject of the study is the methods of analyzing the quality indicators of the computer network of the information system. The results. In this work, an analysis of the main indicators of the quality of the telecommunications network, which are basic in the provision of services. Based on the received information, 6 states of the telecommunication network were formalized and classified, in which it is possible to provide non-essential quality of service for various types of traffic. The developed method of analyzing the quality indicators of the computer network of the information system of critical application is planned to be used in the future to ensure the quality and reliability of the functioning of computer systems of critical application.