This work proposes a small, light, valveless pump design for a portable renal replacement system. By analyzing the working principle of the pump and exploring the design space using an analytical pump model, we developed a novel design for a cam-driven finger pump. Several cams sequentially compress fingers, which compress flexible tubes; thus eliminating valves. Changing the speed of the motor or size of the tube controls the flow rate. In vitro experiments conducted with whole blood using the pump measured Creatinine levels over time, and the results verify the design for the portable renal replacement system. The proposed pump design is smaller than 153 cm3 and consumes less than 1 W while providing a flow rate of more than 100 ml/min for both blood and dialysate flows. The smallest pump of a portable renal replacement system in the literature uses check valves, which considerably increase the overall manufacturing cost and possibility of blood
clotting. Compared to that pump, the proposed pump design achieved reduction in size by 52% and savings in energy consumption by 89% with the removal of valves. This simple and reliable design substantially reduces the size requirements of a portable renal replacement system.