Electrically conducting polypropylene/poly(propylene)-grafted maleic anhydride/layered expanded graphite oxide nanocomposites PP/PP-g-MAH [PPM/layered expanded graphite oxide (LEGO)] have been prepared by masterbatch-melt blending process. The effects of the filler and compounding method on the structure and properties of PPM/LEGO nanocomposites were investigated and reported. Scanning electron microscopy revealed excellent dispersion of LEGO in polymer matrix during the compounding process, as well as deformational features of fracture surfaces. X-ray diffraction and transmission electron microscopy (TEM) exhibited an exfoliated structure of LEGO in polymer. Fourier transform infrared spectra showed possible interfacial interactions between LEGO and matrix. Tensile tests indicated that LEGO had a reinforcing effect on the tensile behavior of PPM. Differential scanning calorimetric results showed that the incorporation of LEGO could increase T-c and X-c of polymer matrix, indicating that the LEGO acted as a nucleating agent for PPM. The nanocomposites prepared by masterbatch-melt blending showed higher conductivity than nanocomposites prepared by conventional direct melt blending. The enhancement of electrical conductivity may be due to more effective dispersion of LEGO sheets in the polymer matrix and strong interfacial interactions between LEGO and matrix, which reinforced the formation of conducting multiple networks. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128: 600-610, 2013