In this study we manufactured highly porous graphite nanofibres (GNFs) by physical activation in order to develop promising energy storage materials. The activation was performed at activation temperatures in the range of 800-1050 degrees C. The pore structures of the porous GNFs were analysed using N2/77 K adsorption isotherms. After the activation, the porous GNFs showed a decrease in diameter and scratches on their surfaces, resulting from surface oxidation and the opening of the graphitic layers, respectively. It was found that the specific surface area of the porous GNFs prepared at 1050 degrees C was more than 2000 m(2) g(-1) without loss of their fibre shape or serious increase in electrical resistivity. This result indicates that porous GNFs prepared under optimal conditions can have a much higher specific surface area and are promising materials for energy storage technologies.