Development of active but earth-abundant electrocatalysts for oxygen evolution remains a great challenge. In this work, we report a one-step organic amine-mediated method to synthesize Fe-Co sulfide composites. Electrochemical results show better oxygen evolution activity of the sulfides obtained with more sulfur dosage and Co-Fe molar ratio in the range of 1:2-2:1. The optimized Fe-Co sulfide presents a lower overpotential of 288 mV at 10 mA cm(-2) in 1 M KOH. The electrocatalyst also shows a considerable long-term stability. During the electrocatalytic process, the involved cobalt species on the surface layer was lost, only leaving oxidized Fe species that would act as catalytic active centers. The excellent catalytic activity can be attributed to the porous structure of the in situ derived active phase, the high conductivity of inner layer metal sulfides, and the residues of sulfur species that may tune the electronic structure of metal sites.