A major factor limiting the use of ultrafiltration (UF) membrane in water treatment process is the membrane fouling by natural organic matter such as humic acid (HA). In this work, neat PVDF and PVDF/TiO2 mixed-matrix membranes were prepared and compared in terms of their antifouling properties. Two commercial types of TiO2 namely PC-20 and P25 were embedded to prepare the mixed matrix membranes via in situ colloidal precipitation method. The contact angles for the mixed-matrix membranes were slightly reduced while the zeta potential was increased (more negatively charged) compared with the neat membrane. Filtration of HA with the presence of Ca2+ demonstrated that mixed-matrix membrane could significantly mitigate the fouling tendency compared with the neat membrane with flux ratio (J/J0) of 0.65, 0.70, and 0.82 for neat PVDF membrane, PVDF/TiO2 mixed-matrix membrane embedded with P25 and PC-20, respectively. PC-20 with higher anatase polymorphs exhibited better antifouling properties due to its hydrophilicity nature. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013