Clinical evaluation of Altra-Flux 140, a new Pliva hollow-fiber type dialyzer showed the clearances and removal rate of small molecular weight solutes to be satisfactory during 4-hour dialysis. The ultrafiltration rate was high, but acceptable when used with volumetric-controlled hemodialysis delivery systems. Biocompatibility was good, and there were no intradialytic symptoms in patients, attributable to the use of Altra-Flux 140. In general, no residual blood was detected. Handling of Altra-Flux 140 was found to be easy and the membrane strength adequate.