The objective of this work is to investigate the effect of graphite addition to Al/SiC composites manufactured by stir casting process. The reinforcement content of graphite was varied from 2.5 wt. % to 7.5 wt. %, for preparing three types of hybrid composites. Al/SiC/Gr hybrid composites prepared by stir casting method have uniform dispersion of SiC and Gr particle reinforcement. High-speed machining of Al/SiC/Gr was done in CNC machine using PCD insert at a cutting speed of 300, 400 and 500 m/min. From ANOVA analysis, cutting speed (48.76%) is the critical factor affecting surface roughness. Grey Relational analysis was done for simultaneous improvement of Material Removal Rate and surface roughness. Roughness values were predicted using Taguchi method and predicted values were compared with experimental results. Elemental chips produced during machining leads to reduced roughness values. © 2020, © 2020 Engineers Australia.