Electrocatalysts for oxygen reduction reaction (ORR) are an important component of renewable energy devices such as fuel cells and metal-air batteries.^1-3 Among the catalysts studied, nitrogen doped graphene with high activity and good stability in alkaline medium has been viewed recently.^4,5 However, their insufficient catalytic ORR activity when compared with Pt-based catalysts still remains a great challenge. More importantly, the resulting catalysts yield ORR activity in base but poor ORR activity in acidic solutions. Recently, the integration of 2D graphene sheets into 3D porous structures, such as crumpled graphene and graphene foam, has generated great interest due to their exceptional porous configuration (large surface area, high porosity) and wide practical applications (electronics, energy storage and convention, sensor).^6,7 Here, we demonstrated that 3D porous N-doped graphene foam prepared from a hard templating approach could act as a highly efficient ORR catalyst. Very interesting, at the same mass loading, the catalysts exhibit pronounced electrocatalytic activity towards ORR with onset potential of 1.01 V in 0.1M KOH, which is comparable to that of Pt/C. At potential lower than 0.88 V versus reversible hydrogen electrode, the current density of the porous graphene is even greater than that of Pt/C. Besides, the porous graphene catalyst also has an excellent ORR activity and long-term stability in acdic condtions (0.1M HClO₄). The porous graphene was characterized by extensive methods including transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, inductively coupled plasma (ICP) and Brunauer−Emmett−Teller (BET) surface analysis. It is found that the large surface area, unique porosity, and small amounts of irons in the catalyst are responsible for the outstanding catalytic performance.