In this work, the effect of graphene nanoplatelets (GNPs) addition in the mechanical, thermal and electrical properties of carbon fiber composites was studied. GNPs were incorporated into benzoxazine matrix and nanocomposites with a 0.5 and 2 wt.% of graphene nanoplatelets were manufactured. The effect of this nanoreinforcement in benzoxazine mechanical properties as well as in its thermal and electrical conductivity was evaluated. Carbon fiber composites has been manufactured by means of liquid resin infusion (LRI) technique using the nanocomposites prepared. The manufacturing process with the nanocomposite containing a 2 wt.% of GNPs presented some filtration problems which hindered its characterization. The laminate with a 0.5wt.% of nanoreinforcement showed an increase in both thermal and electrical conductiviy regading to the panel with unmodified benzoxazine.