A medical infusion pump system comprising: a pump device including: a pump housing that defines a space to receive a medicine cartridge that occupies a majority of a length of the pump housing; a drive system housed in the pump housing to dispense medicine from the cartridge when the cartridge is received by the pump housing, the drive system including a piston rod that is incrementally movable longitudinally into the medicine cartridge to apply a dispensing force; one or more electrical contacts disposed on the pump housing, at least a portion of the drive system being in electrical communication with the one or more electrical contacts; and a removable controller device (200, 300) including: a controller housing that is removably attachable to the pump housing in a fixed relationship, the controller housing defining a cavity in which at least a portion of the pump device is receivable; one or more electrical contacts disposed on the controller housing, the electrical contacts of the controller device (200, 300) being engageable with the electrical contacts of the pump device when removably attached; a user interface arranged on the controller housing, the user interface including a display and one or more user-selectable buttons (224a 224b) wherein the pump device and the controller device (200, 300) when removably attached, provide a hand-graspable portable unit. a pump device including: a pump housing that defines a space to receive a medicine cartridge that occupies a majority of a length of the pump housing; a drive system housed in the pump housing to dispense medicine from the cartridge when the cartridge is received by the pump housing, the drive system including a piston rod that is incrementally movable longitudinally into the medicine cartridge to apply a dispensing force; one or more electrical contacts disposed on the pump housing, at least a portion of the drive system being in electrical communication with the one or more electrical contacts; and a pump housing that defines a space to receive a medicine cartridge that occupies a majority of a length of the pump housing; a drive system housed in the pump housing to dispense medicine from the cartridge when the cartridge is received by the pump housing, the drive system including a piston rod that is incrementally movable longitudinally into the medicine cartridge to apply a dispensing force; one or more electrical contacts disposed on the pump housing, at least a portion of the drive system being in electrical communication with the one or more electrical contacts; and a removable controller device (200, 300) including: a controller housing that is removably attachable to the pump housing in a fixed relationship, the controller housing defining a cavity in which at least a portion of the pump device is receivable; one or more electrical contacts disposed on the controller housing, the electrical contacts of the controller device (200, 300) being engageable with the electrical contacts of the pump device when removably attached; a user interface arranged on the controller housing, the user interface including a display and one or more user-selectable buttons (224a 224b) a controller housing that is removably attachable to the pump housing in a fixed relationship, the controller housing defining a cavity in which at least a portion of the pump device is receivable; one or more electrical contacts disposed on the controller housing, the electrical contacts of the controller device (200, 300) being engageable with the electrical contacts of the pump device when removably attached; a user interface arranged on the controller housing, the user interface including a display and one or more user-selectable buttons (224a 224b) wherein the pump device and the controller device (200, 300) when removably attached, provide a hand-graspable portable unit.