The present invention is a more efficient compressor control system and a more efficient method of operating a multiple compressor system because the method and control system are a function of both the system pressure and the volumetric flow rate capacity of the system. Specifically, a compressor is loaded or unloaded from the compressor system after sensing the actual system pressure and volumetric flow rate capacity. The inventor(s) of the present invention have discovered that it is more efficient to control the compressors upon sensing both the pressure and volumetric flow rate capacity of the fluid. Moreover, controlling the compressor system in response to sensing both the pressure and volumetric flow rate capacity of the fluid insures that the appropriate blend of compressors is loaded to the system in order to produce the most suitable pressure and volumetric flow rate capacity. In other words, the control system of the present invention loads the most appropriate compressors to the system in order to produce the most suitable pressure and volumetric flow rate capacity and minimizes the production of any excessive amounts thereof. Thus, controlling the compressors in response to both a change in pressure and a change in the volumetric flow rate capacity prevents the unwarranted utilization of electrical power, thereby producing a more efficient compressor control system.