The research of new polymeric materials for membrane application in the field of narrofiltration is of great interest. PEEKWC, a modified polyetheretherketone with a cardo group, is a polymer character zed by high thermal, chemical and mechanical properties and then useful for application in the nanofiltration field. In this work, the preparation and characterization of different PEEKWC membranes by non-solvent induced phase inversion for nanofiltration of aqueous solutions containing Azur B and maltose were discussed. Interesting results in terms of retention and relative flux were obtained compared to the performance of two commercial membranes, N30F and NFTFC50. Tuning the preparation conditions, size of pores and roughness of the PEEKWC membranes can be varied with consequent effects on the membrane performance. (C) 2009 Elsevier Ltd. All rights reserved.