For its wide availability and low cost, nickel is a promising candidate to be used as a cocatalyst in Pt-based catalysts for proton exchange membrane fuel cells. Among Pt-M (M=transition metal) catalysts for oxygen reduction, Pt-Ni is the one which can be used in various forms, that is, as disordered Pt1-xNix solid solutions, ordered intermetallic phases, octahedral-shaped structures (with a preferential {111} facet orientation), dealloyed structures, and hollow and 1-dimensional nanostructures. In this work, an overview of the oxygen reduction on Pt-Ni and Pt-Ni-M (M=Co, Fe, Cu) catalysts and their stability in proton exchange membrane fuel cell environment is presented.