In this work, preparation of nanocrystalline Ni3Al-based alloys by mechanical alloying process followed by hot-pressing consolidation is reported. Ni75Al20Co5 and Ni70Al25Co5 elemental powder mixtures were subjected to ball milling. Subsequently, the milling products were sintered at 1000oC under a pressure of 7.7 GPa. The powders and the consolidated pellets were investigated by X-ray diffraction. The results obtained show that the milling products were in both cases supersaturated solid solutions Ni(Al,Co) and that during hot-pressing consolidation they had transformed into nanocrystalline Ni3Al-based intermetallic compounds. The microhardness of the produced Ni3Al-based alloys is 920 HV0.1 in the case of Ni75Al20Co5 composition and 1030 HV0.1 in the second case. The density of compacted materials is close to the theoretical value and their open porosity is negligible.