A foam dispenser having a selectively pressurized cartridge that includes a dispenser housing maintaining a motor driving an air compressor with a compressed air conduit extending therefrom. Also maintained within the dispenser is a foam generating head that receives air and liquid conduits that include dispensing valves. A control circuit controls the motor and dispensing valves, and further is interconnected with a hand sensor positioned in association with the dispensing head. In one embodiment of the invention, a disposable and replaceable cartridge of liquid soap or the like is adapted to sealingly and removably receive the compressed air conduit as well as the liquid and air outlet conduits, along with a vent valve and a pressure sensor, the vent valve and pressure sensor communicating with a control circuit. In another embodiment, the various conduits, valves and sensors, as well as the dispensing head, comprise a portion of the cartridge. The control circuit, upon sensing the presence of the user's hands, activates the motor and air compressor to generate a pressure head in the cartridge and the dispensing valves are activated when the pressure sensor determines that a pressure head sufficient for dispensing has been generated. The motor and compressor are turned off at an appropriate time in association with the activation of the dispensing valves. The vent valve is activated at the end of the dispensing cycle.