This paper describes the control of refrigeration systems. The goal of the research is to support the design of refrigeration systems and to define the optimum parameters that influence refrigerating systems. A second aim of the investigation was an analysis of currently available control equipment for refrigeration systems and the producers. The equipment can be divided into two segments: equipment for the control of simple refrigeration systems, which consists of electronic thermostats for controlling the elements of the refrigeration rooms; and miniature microprocessor-based equipment used for controlling the smallest compressor aggregates. The advantages of this equipment are its his wide consumption, low cost and simple usage. Its drawbacks are inappropriateness for complex refrigeration systems in the senseof increasing the coefficient of performance (COP) and the consumption ofelectrical energy. The main emphasis of the paper is on the control of complex refrigeration systems based on programmable microprocessors and SCADA (supervisory control and data acquisition) systems.