Active, stable, earth-abundant and cost-effective electrocatalysts are important to water splitting for producing oxygen and clean fuel hydrogen. Here we report a facile one-pot hydrothermal assembly of three-dimensional (3D) reduced graphene oxide (RGO)-Ni-Fe oxide hybrid foams as an effective electrocatalyst for oxygen evolution reaction (OER). It was found that in the one-step hydrothermal process, only in a narrow pH range around 3.5, the 3D RGO foam can be formed with non-precious nickel-iron oxide nanoparticles (< 5 nm) embedded in the porous structure of the foam. The as-prepared 3D structured RGO foams provide an effective network for electron transfer, massive pore structures for ion transport, and large surface areas for reaction. The electrochemical properties of RGO-Ni-Fe foams were investigated by using a three-electrode system under alkaline conditions, with the OER properties comparable to those of iridium catalyst and other superior Ni-Fe catalysts. (C) 2016 The Electrochemical Society. All rights reserved.