Polymeric membranes have low mechanical, chemical, and thermal resistances, whereas carbon nanotubes (CNTs) have excellent mechanical properties, in addition to high chemical and thermal stability. Hence, polyacrylonitrile/multiwalled CNT (PAN/CNT) nanocomposite fibers were synthesized via an electrospinning process in order to modify the properties of PAN nanofibers. The resultant nanofibers were then characterized by scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. It was found that the addition of CNTs into the polymer solution increased the roughness of the fiber surface. The diameters of the PAN, 0.1% CNT doped PAN and 0.5% CNT doped PAN nanofibers are 1.63, 0.59 and 1.39 mu m, respectively. Hence, the thickness of the nanocomposite fiber was seen to be dependent on the CNT concentration. The protein adsorption onto the 0.1% CNT doped PAN nanofibers and 0.5% CNT doped PAN nanofibers were 26% and 34% less than the PAN nanofibers, respectively. Hence, adding CNTs to the PAN/CNT nanocomposite fibers also had the potential to alleviate fouling. Based on these results, the modification of PAN/CNT nanocomposite fibers was confirmed, and these fibers were deemed to be a good alternative to current support materials for membranes.