In this study, the fouling behavior of TiO2-polyethylene hybrid membranes was analyzed. Initially, high density polyethylene (HDPE) membranes embedded with TiO2 nanoparticles were fabricated via thermally induced phase separation (TIPS) method. FESEM images showed that the membranes had leafy structure indicating solid-liquid phase separation mechanism. The results of XRD analysis confirmed the presence of TiO2 nanoparticles in the polymer matrix. AFM images showed that the surface roughness of TiO2 embedded membranes were higher than that of neat HDPE membrane. Pure water flux of membranes improved as the TiO2 content increased. The fouling behavior of membranes was investigated by filtration of collagen protein solution. The governing fouling mechanisms of membranes were also investigated using classic models as well as combined fouling models. The results showed that the best model fitted into the experimental data for 0.50, 0.75 and 1.0 wt.% TiO2 embedded HDPE membranes was the cake filtration model. For neat and 0.25 wt.% TiO2 embedded membranes, however, cake filtration-complete blockage model was in good agreement with the experimental data. Moreover, addition of TiO2 nanoparticles increased reversible portion of fouling. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.