The manual is dedicated to the main issues that the system administrator should own. System tools for administration of information systems, computer networks and databases from Microsoft and application software are considered. Studying theoretical aspects will form the theoretical basis necessary to start working as a system administrator. The textbook complies with federal state educational standards of higher education in the areas of training "Information Systems and Technologies" and "Mathematical Support and Administration of Information Systems" and can be used by students studying under the program of both bachelor's and master's degrees. If necessary, the manual can be used for other areas of training, in which appropriate disciplines can be introduced.