Iron-nickel alloys with compositions ranging from pure iron to pure nickel at increments of 10 wt% have been prepared by mixing fine elemental carbonyl iron and nickel powders, and sintering at temperatures between 1200-1350 degrees C. The addition of nickel to iron promoted densification and avoided abnormal grain growth at low concentrations. However the densification was retarded when the iron and nickel had approximately equivalent concentrations. As the concentration of nickel increased, the room temperature structures of the alloys gradually changed from alpha-Fe into gamma-(Fe, Ni), with Fe-30 wt% Ni and Fe-40 wt%, Ni containing both phases. The relative abundance of each phase was determined by the degree of compositional homogeneity achieved in sintering.