The present invention comprises a method and system for refilling printer ink cartridges. The method and system refill the cartridge while under a vacuum, and provide a positive displacement, peristaltic pump that is automatically operated a precise amount of time to ensure that the proper amount of ink is added to the cartridge. In addition, the filling pump's operation is periodically paused during the refilling process to ensure that air within the foam sponge that retains the ink typically in most printer cartridges can migrate out of the sponge.