Multiwalled carbon nanotubes modified with triethylenetetramine (TETA) as an organic nanofiller was used in fabrication of polyvinyl chloride (PVC) nanofiltration membranes. The membranes were prepared by the phase separation method and immersion precipitation technique. For this purpose, various percentages of the TETA-MWCNTs were added to the casting solutions and the membrane films were formed and placed in a bath water. In order to identify the membranes and their properties, SEM images, contact angle and FTIR-ATR analyses were taken from the prepared nanocomposite membranes. The membranes performance in terms of water/protein/dye permeability, protein rejection and Lanasol blue 3R dye rejection were investigated. Establishing hydrogen bond between the water molecules and the functional groups of MWCNTs enhanced the hydrophilicity of the fabricated membranes and caused an increase in permeability. The permeability in the membrane containing 0.25 wt% of TETA-MWCNTs reached its highest value, and adding more amounts reduced flux by blocking the membrane pores. There was also a significant decrease in the rate of membrane fouling for the hybrid membranes. Flux recovery ratio reached from 62.2% to 76.1%. Also, rejection of BSA and Lanasol blue 3R combination dye was increased for the modified membranes.