Elemental Powders of Al and Ni with the composition of Al₅₀Ni₅₀ was mechanically alloyed in an Ar gas atmosphere for various periods using a horizontal ball mill. A single phase of AM compound (B2:ordered BCC) was synthesized by milling longer than 360ks. The powder particle size was substantially decreased to about 0.5 μm in diameter by MA associated with the formation of AlNi compound. The MA powders were hot-pressed under the condition of 150MPa at 973K for 1.8ks. The hot-pressed compacts showed compositional inhomogeneity when powders were milled shorter than 72ks. When MA time is longer than 180ks, the unsintered region appeared in the hot-pressed compact and the area increased with the increase in MA time. The powder milled for 1800ks did not sinter at all. The hardness of hot-pressed compacts showed maximum of 500Hv at MA time of 18ks and reduced gradually with MA time. The suitable MA time for sintering was considered to be around 100ks.