Recently, metal matrix Nano composites are considered a leading material. The attention of Nano particles reinforced aluminum is increased due to excellent properties. The machinability of these materials is difficult due to high hardness and abrasive nature of reinforcement elements like aluminum oxide (Alumina) particles. In this investigation, aluminum silicon alloy reinforced with homogeneous 0.5% and 1% by volume of aluminum oxide Nano particulates were used as workpiece material. The stir casting route was used to fabricated the workpiece material . The concentration of Nano reinforced particles, cutting speed, feed rate and depth of cut are selected as process parameters in dry turning. While surface roughness, roundness error and metal removal rate are considered as evaluating parameters for machinability of metal matrix nano composites. Taguchi method was used to design these experiments. The experimental results have been analyzed using both signal to noise ratios and ANOVA.The results obtained showed that feed rate was the most significant parameter on surface roughness followed by aluminum oxide Nano particulates% while, aluminum oxide Nano particulates% was the most significant parameter on roundness error followed by feed rate and the most significant parameter on MRR was depth of cut followed by cutting speed.