Currently, one of the significant elements of control systems for critical infrastructure objects (transport, oil, and gas industry objects, energy objects) is the use of operator support systems. The paper discusses the problems of the operator support system (OSS) with their assignment to groups in terms of system organization, tracking signals coming from the control system, and execution time. The relationship between the functional parts of the OSS and the system’s external environment had shown. The connection between the OSS, the process control system, and other diagnostic systems had considered. The use of operator support systems makes it possible to increase the safety and efficiency of the operation of a critical infrastructure object and reduce the number of incidents and emergencies due to the human factor.