Effects of the compounding equipment, the viscosity of the matrix, and the annealing on the electrical resistivity of polycarbonate (PC)/MWCNT nanocomposites were investigated. Two different types of compounding equipment (a batch mixer and a twin screw extruder) produced a huge difference in the resistivity in an injection molded PC/MWCNT nanocomposite while the resistivity of compression molded samples showed only small differences. It was also observed that the viscosity of the PC matrix affected the resistivity of the injection molded nanocomposites to a great extent. The resistivity of the nanocomposites increased with the viscosity of the PC matrix. This is attributed to two factors. When the PC/MWCNT nanocomposites are fabricated, interpenetration of the PC matrix into MWCNT bundles is easier for a less viscous matrix. Another factor is that lower viscosity PC induces less orientation of MWCNTs. (C) 2016 Elsevier Ltd. All rights reserved.