We investigated electrical conductivity of PP/MWCNT nanocomposites prepared by both compression and injection molding. Six different MWCNTs were used in this study. Among them, two set of MWNCTs have same aspect ratio but different bulk density. In most previous studies investigating the effect of bulk density, two different MWCNTs have not only different bulk density but also different aspect ratios. Thus, it is not clear to isolate the effect of bulk density from the aspect ratio. Through various investigations, we found that the bulk density of MWCNTs is a more crucial factor affecting the dispersion state and final electrical properties of the composite rather than the aspect ratio.