A water soluble chitosan derivative, N-succinyl chitosan (NSCS), was blended with polysulfone (PSf) in three different compositions to fabricate PSf/NSCS blend membranes. The blending of polymers was confirmed by Attenuated Total Reflectance Infra-Red (ATR-IR) spectroscopy. The membranes were characterized by Scanning Electron Microscopy (SEM) images for their cross-sectional morphology. Pure water flux, water uptake and contact angle of the PSf/NSCS blend membranes were measured and compared with the pristine polysulfone membrane. The PSf/NSCS blend membranes showed enhanced hydrophilicity and permeation fluxes compared to the pristine polysulfone membrane. The membrane antifouling property was determined by filtering the bovine serum albumin (BSA) solution. The maximum flux recovery ratio (FRR) of 70% was observed by the PSf/NSCS blend membrane with 20% NSCS content. The PSf/NSCS membranes with the PSf:NSCS ratios of 80:20 and 90:10 showed nearly the same fluxes as those of polysulfone/polyethylene glycol (PSf/PEG) blend membranes with the same compositions. The hydrophilic derivative of chitosan NSCS acted as an excellent additive in improving PSf ultrafiltration properties. (C) 2013 Elsevier B.V. All rights reserved.