The article is devoted to the development of a method for evaluating the effectiveness of the level of protection at the object of information activities when using an integrated security system. Such systems provide for the sharing of resources of subsystems of fire and security alarm, video surveillance, access control systems and others. The application of integration provides a number of benefits, including: quick and accurate reaction to events, facilitating the work of the operator by automating management processes, control and decision-making on security, reducing the probability of erroneous actions of the operator, reducing equipment costs. Among the requirements for integrated security systems are reducing the role of man in the security process by increasing the systems intelligence, reducing the level of false positives due to closer use of subsystems and openness. Implementation of these requirements will increase the efficiency of security systems, reduce the human factor and will make the construction of integrated systems more transparent. The proposed method of assessing the integrated security system summarizes the state of security at the object of information activities, points to the weaknesses of the existing integrated security system, those that need of improvement. It can also be used when selecting the appropriate integrated security system. The assessment of the level of protection takes into account such criteria as complexity, functionality, size, speed, fault tolerance, scalability, interaction with external systems, the possibility of expansion.