The aim of this work was the exploration of a potential biocompatible membrane prepared from a modified polyetheretherketone (PEEK-WC). The physico-chemical properties of PEEK-WC were characterised by Differential Scanning Calorimetry and FT-Infrared Spectroscopy. The surface affinity of this membrane to human plasma and proteins such as albumin, fibrinogen and immunoglobulins G was evaluated and compared with that of commercial membranes. The wettability of all investigated membranes was established by water contact angle measurements. PEEK-WC membranes exhibited moderate wettability and low protein adsorption, differently from other commercial membranes such as cellulose acetate membrane. A preferential adsorption of hydrophilic proteins as albumin on the membrane surfaces was observed. Human plasma adsorption on membranes followed the same trend as individual protein solutions.