Elemental powders of Al and Ni with the composition of Al₇₅Ni₂₅ was mechanically alloyed in an Ar gas atmosphere for various periods using a horizontal ball mill. A single phase of disordered AlNi structure (BCC) was obtained by milling of 1800ks. This BCC structure transformed into Al₃Ni compound (DO₂₀) at around 600K. The hot-pressed compacts of MA powders showed compositional inhomogeneity and voids produced by isothermal solidification when powders were milled shorter than 72ks and showed well sintered structure when powders were milled longer than 180ks. The hardness of hot-pressed compacts prepared from MA powders milled between 36ks and 360ks reached at around 750Hv. The suitable MA time for sintering was considered to be between 180ks and 360ks.