The aim of the European project Nephron+ is the design of a wearable artificial kidney device. This paper is focused on the design of the corresponding ultralow-hemolysis continuous-operation blood pump. Accurate specifications and operating principle of the pump are determined. A first nonoptimal configuration of a linear electromechanical actuator which will be used to pump the blood is designed. Its prototype is presented along with the corresponding driving electronic circuit. Finally, based on the measurements, the actuator is optimized, and the final design and first experimental results are presented.