The identity of the active species toward the oxygen reduction reaction (ORR) in nonprecious metal catalysts remains elusive, impeding the rational design of new catalysts. Herein, Fe1–xNixnanoparticles decorated with bamboo-like N-doped carbon nanotubes (Fe1–xNix–N/C) were in situ grown via direct pyrolysis of the metal salts and the melamine mixture at 800 °C under a N2stream. By tuning of the atomic ratio of Fe and Ni, it is found that Fe0.75Ni0.25–N/C and Fe0.5Ni0.5–N/C exhibit superior catalytic activity toward ORR. The catalytic activity is closely related to the crystal structure and the unit cell parameter of the Fe1–xNixnanoparticles. It is suggested that besides the generally proposed synergetic effect between the Fe1–xNix-alloyed nanoparticles and the N-doped carbon nanotubes the magnetic ordering is likely to be an important factor for the enhancement of catalytic properties of Fe1–xNix–N/C catalysts. In addition, it is found that bimetallic γ-Fe1–xNixnanoparticles show better chemical stability compared with the monometallic nanoparticles and the α-Fe1–xNixnanoparticles. Fe0.75Ni0.25–N/C and Fe0.5Ni0.5–N/C retain good catalytic activity after being stored in air for one year.