Daily dialysis offers many benefits but is difficult to implement. CRRT allows dialysis 24/7 but is not suitable for ESRD patients. Thus, the need for a miniaturized ambulatory CRRT device those patients can wear permanently. We report the feasibility, safety and efficiency in uremic pigs, of such a wearable artificial kidney (WAK) that can be worn as a belt, operated with batteries, and weights less than 5 lbs. We used a hollow fiber dialyzer with a surface area of 0.2 sqm. Dialysate was continuously regenerated by a series of cartridges containing several sorbents allowing the use of approximately 375 ml of dialysate. The device includes reservoirs with heparin and electrolytes. Average fluid removal was 100 ml/hr. The Creatinine was 25 ml/min. In 8 hrs the total Creatinine removed was 1 gr, Urea 12 gr, P0.8 gr and K 72 mEq. Weekly st kt/v was extrapolated to approximately 7. There were no side effects. The WAK can be operated safely and continuously 168 hr/week. This would allow for all the advantages of daily dialysis and reduce morbidity and mortality in the ESRD population. It will also reduce cost and manpower utilization.