Peritoneal dialysis is a treatment for kidney failure, using the peritoneum, i.e., the lining of the abdomen, to filter blood (e.g., removing excess fluid, correcting electrolyte problems, and removing toxins) in end-stage renal disease patients. The treatment might be quite easily done overnight at patient home by using a device for Automated Peritoneal Dialysis (APD). The latter, called cycler, consists of a pumping system filling and emptying patient’s belly three to five times during the night. This study aimed at evaluating the fluid dynamic performance of two prototypes of diaphragm pumps for APD cassette system. The first model, named Pump 2, consisted of an elliptical chamber limited on the top by a membrane and equipped with a piston allowing for fluid motion.