WHEN USED FOR ENGINEERING APPLICATIONS, METAL MATRIX COMPOSITES (MMC) ARE OFTEN MACHINED. THIS PAPER INVESTIGATES THE MACHINABILITY OF AN EXPERIMENTAL ALUMINA- CONTAINING MICROSPHERE USING A REINFORCED 6061 ALUMINUM ALLOY. THE TURNING DATA WAS COMPARED WITH THAT OBTAINED FOR A SIMILAR MMC WHICH WAS REINFORCED WITH ANGULAR AL 2 0 3 PARTICULATES. TOOL FLANK WEAR, CUTTING FORCE, AND WORKPIECE SURFACE FINISH WERE MONITORED AT REGULAR INTERVALS. EXCELLENT MACHINABILITY CRITERIA HAVE BEEN ACHIEVED FOR THE COMPOSITE.