A closed-loop vacuum control system for a powered breast pump is the subject of the present disclosure. The vacuum control system includes a source of vacuum for applying a vacuum to a milk collection kit. It also includes a device for setting the vacuum level to be produced by the source of vacuum to a preselected vacuum level. The vacuum control system further includes a sensor for sensing the actual vacuum level being produced by the source of vacuum during operation. A controller continuously compares the preselected vacuum level with the actual vacuum level. A proportional valve is also provided for adjusting the actual vacuum level to correspond to the preselected vacuum level. In this manner, the proportional valve can adjust the actual vacuum level in response to a signal from the controller.
