In this research, the modification of emulsion polyvinyl chloride (EPVC) filtration membranes was evaluated by incorporating tungsten trioxide (WO3) nanosheets. The WO3 nanosheets at five different percentages were blended with the polymeric casting solution to prepare flat sheet membranes via the phase separation method. The prepared nanocomposite membranes were characterized by SEM, AFM, ATR, mean pore radius, porosity, and contact angle measurements. The investigated parameters were water flux, rejecting protein and three dyes, antifouling ability, long-term test and reuse ability. The obtained results showed that adding an optimal amount of WO3 (1 wt%) enhanced water flux and dye rejection. The nanocomposite membranes presented a lower contact angle due to the hydrophilicity of inserted WO3 nanosheets. The water permeability increased from 191 L/m(2)h.bar for the bare membrane to 238.8 L/m(2)h.bar for 1 wt% WO3 EPVC membrane with 96.6, 95.4 and 57.5% rejection rates for Reactive Green 19, Reactive Red 195 and Reactive Yellow 39 solutions with molecular weights of 1419, 1136.31 and 699.2 g/mole, respectively. The long-term test and reuse ability performance showed that the dye rejection did not change sensibly and good resistance was observed against the flux reduction. In conclusion, WO3 can be applied as a suitable nanosheet to modify PVC membranes. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.