A six-year-old Rottweiler with chronic ascites and moderate panhypoproteinaemia that had been treated with large volume paracentesis over several months duration was diagnosed with a large bi-atrial mass and hepatic fibrosis. For palliative treatment, a peritoneo-vesical automated fluid shunt system with an integrated chargeable battery and an integrated computer to control pump function and to transmit data transcutaneously was implanted by coeliotomy. The pump was left in place for 10 weeks, eliminating the need for further paracentesis during this time. At the end of this period, no ascites was discernible and serum protein concentrations had returned to their respective reference intervals. As a complication, decubitus with skin perforation had developed above the pump. Besides palliative treatment of chronic refractory ascites, this pump may have application in other conditions characterised by chronic cavity effusion or in peritoneal dialysis.