Dual layer hollow fiber membranes, based on poly(ether sulfone), were fabricated to achieve hydrophilic membranes with improved fouling resistance. A new triblock copolymer, consisting of two hydrophilic poly(ethylene oxide) blocks and an inner poly(ether sulfone) block, was chosen for the functionalization of the inner layer. The most promising membrane of this study was characterized by an improved hydrophilicity, and a performance in the ultrafiltration studies of 2000 L m−2h−1bar−1 and retention of 100 kDa.