Considering the continuous increment of morbidity in patients with renal disease, the improvement of polymeric membranes characteristics for haemodialysis is a challenging issue. The efficient removal of middle size uremic toxins, as well as biocompatibility is crucial characteristics to ameliorate chronic kidney disease patients' outcomes. In this study, polysulfone membranes with different hydrophilic additives, molecular weight and concentrations were prepared by spin coating method, followed by phase inversion via immersion precipitation. The removal of urea, lysozyme and bovine serum albumin was studied using a miniaturized flow system, mimicking haemodialysis conditions. The optimal composition was 15.0 wt% of polysulfone and 2.5 wt% of polyvinylpyrrolidone K30. This selected membrane was fully permeable for urea, showed up to 50% rejection of lysozyme and very high rejection of albumin. The additive PVP K30 played important role in the improvement of porosity, without compromising the mechanical strength of the membrane. The biocompatibility of membrane was evaluated by material-induced haemolysis and platelet activation tests. The platelet activation and haemolysis were negligible, compared to other biocompatible materials. These results confirmed the haemocompatibility of the optimized membrane. Therefore, the membrane is not expected to modulate the biological response, when used for the haemodialysis treatment.