CuO/PES composite membranes were fabricated through phase inversion method, focusing on fouling reduction and improving separation performance. Copper oxide nanoparticles were used as filler additive in the membrane structure. The effect of the embedded CuO nanoparticles on the morphology was studied by considering SEM, SOM and 3D surface images. Flux recovery ratio (FRR%), water contact angle, water content, mechanical tensile strength, porosity and mean pore size, salt rejection and water flux were investigated to evaluate the performance of fabricated membranes. The SOM images showed a uniform surface for the modified membranes. SEM images showed a finger-like structure for the modified membranes. Results also denoted an increment in porosity and mean pore size of membrane at low concentration of CuO NPs, whereas the opposite trend was found at higher concentration of nanoparticles. Utilizing CuO NPs enhanced the membrane tensile strength obviously. PWF significantly was improved by applying CuO NPs in membrane matrix. Highest PWF (42.63 L/m2h) was observed for PES-0.05 wt% CuO blended membrane, whereas it was 10.41 (L/m2h) for pristine ones. Salt rejection also measured 82% for virgin membrane and 63-90% for modified membranes. Moreover, FRR% were measured (~77% to ~93%), while the pristine membrane showed ~63% FRR%.