A method for priming a hemodialyzer is disclosed. Hemodialyzer comprises a dialysate compartment, a blood compartment, and a dialysis membrane separating the dialysate and blood compartments. The method comprises the steps of delivering a liquid to a dialysate inlet of the dialysate compartment at a first volumetric delivery rate, passing the liquid through the dialysate compartment from the dialysate inlet to a dialysate outlet of the hemodialyzer and delivering the liquid from the dialysate outlet at a second volumetric delivery rate that is less than the first volumetric delivery rate so as to cause a net flow of the liquid from the dialysate compartment to the blood compartment through the dialysis membrane.