As a potential solution for water scarcity, the membrane bioreactor (MBR) has attracted much consideration in the field of wastewater treatment. In any case, MBRs have fouling issues which lead to a short membrane life and high operational costs. Henceforth, better antifouling polysulfone (PSU) nanocomposite membranes blended with polyethylene glycol functionalized carbon nanotubes (PEG-CNTs) were developed via non-solvent induced phase separation (NIPS) method. CNTs were chemically functionalized with PEG and their successful preparation was confirmed by SEM, FTIR, TGA, and XRD analyses. The fabricated nanocomposite membranes were characterized with respect to water uptake, hydrophilicity, bulk porosity, mean pore radius, and tortuosity. The effect of PEG-CNTs on the membrane morphology and mechanical strength was investigated by scanning electron microscope (SEM) and tensile testing, respectively. The filtration performance of nanocomposite membranes was evaluated by the filtration of water and protein solution. According to the results, the optimum blending of 0.25 wt% PEG-CNTs exhibited an approximately four-fold increase in water and protein permeabilities of 16.8 + 0.5 and 10.8 + 0.8 Lm(-2)h(-1) bar(-1), respectively. Moreover, the addition of PEG-CNTs in polysulfone membranes reduced the interaction between protein and membrane surface, thus improving the fouling resistance by 72.9 +/- 1%. The optimized nanocomposite membrane could be a promising material with enhanced fouling control for wastewater treatment by MBR.