In this study, mixed matrix polyethersulfone based nanofiltration membranes were prepared by composite CoFe2O4/CuO nanoparticles. The CoFe2O4/CuO nanoparticles were synthesized by a chemical precipitation technique, and then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Then, the effect of embedded CoFe2O4/CuO nanoparticles into PES based NF membrane on its physico/chemical properties, separation performance and antifouling ability was studied. The atomic force microscopy (AFM), scanning electron microscopy (SEM), water contact angle, pure water flux, salt rejection, antifouling ability, as well as heavy metal ions separation were used in membrane characterization. The blended membranes with CoFe2O4/CuO exhibited higher surface hydrophilicity and smoother surface than the bare membrane. The water contact angle and average surface roughness reduced from (70 degrees to 35 degrees) and (45 nm to 24 nm) for the bare PES membrane and blended [PES-0.5 wt% CoFe2O4/CuO] membrane, respectively. The PWF measured 34.5 (L/m(2)h) for the blended [PES-0.5 wt% CoFe2O4/CuO] membrane and 12 (L/m(2)h) for the bare ones. The NaCl and Na2SO4 rejection were increased from (32% to 72%) and (62% to 95%) by introducing CoFe2O4/CuO into the PES matrix. The FRR measured similar to 42% for bare membrane whereas that was similar to 90% for the superior blended membrane with 0.5 wt% CoFe2O4/CuO nano particles. The Cu2+, Ni2+ and Pb2+ rejection measured 98%, 92% and 88% for the blended [PES-0.5 wt% CoFe2O4/CuO] membrane whereas they were 85%, 80% and 78% for the pristine PES membrane. The reusability study for the superior blended membrane showed a slight decrease in average performance less than 4.9%.