An infusion pump system is disclosed for dispensing liquid medication, such as insulin. The infusion pump system includes a first reservoir for storing liquid medication, a first fluid driver for exerting pressure on the first reservoir, a second reservoir for storing liquid medication, and a second fluid driver for exerting pressure on the second reservoir. One or more valves are used to permit flow of liquid medication from the first reservoir to the second reservoir, and to permit flow of liquid medication from the second reservoir to an infusion site. Each of the valves is selectively opened or closed to fill the second reservoir with liquid medication from the first reservoir and to dispense liquid medication from the second reservoir to the infusion site. A controller and one or more sensors are used to monitor and control the system.