This study attempts to investigate the thermal conductivity behavior of epoxy nanocomposites containing different types of nanofillers, such as 1-D Multiwall Carbon Nanotubes (MWCNTs) and 2-D predominant shape of Exfoliated Graphite nanoparticles (EG) at loading level from 0.25 to 3% wt. For all the analyzed epoxy nanocomposites calorimetric investigation shows that EG nanoparticles accelerate the curing process of the epoxy resin. Thermal conductivity measurements show that this acceleration is directly related to the better heat conduction obtained through the incorporation of EG in the epoxy matrix. The thermal conductivity of epoxy nanocomposites filled with EG, unlike of epoxy nanocomposites containing MWCNTs, increases significantly with increasing content of nanofiller. An increase in thermal conductivity of approximate to 300% has been detected for a filler percentage of only 3%wt of EG. The application of Deng-Zheng micromechanical model has proven to be very effective in predicting analytically the thermal conductivity of the analyzed nanocomposites. POLYM. ENG. SCI., 57:779-786, 2017. (c) 2017 Society of Plastics Engineers