Ni/graphene sheets were synthesized from graphene oxide sheets using electroless Ni-plating in a NiSO4 solution, with NaBH4 as a reducing agent. The samples were characterized by X-ray diffraction, scanning and transmission electron microscopy. Ni deposited on the surface of the reduced graphene oxide sheets had a high dispersion without aggregation, although the amount of Ni was as high as 32.9% by mass. The stacking of Ni/graphene sheets resulted in the formation of meso- and macropores. Nitrogen adsorption showed that the meso- and macropores had a slit shape and that the Brunauer-Emmett-Teller specific surface area reached 91 m2/g. The average pore size calculated by the Barret-Joyner-Halenda method from desorption studies was 3.83 nm, with a pore volume of 0.28 cm3/g.