The optimum joining parameters for the friction joining of aluminium-based metal-matrix composite (MMC) materials are examined. The properties of MMC/MMC, MMC/alloy 6061 and alloy 6061/alloy 6061 joints are derived following detailed factorial experimentation. The mechanical properties of the joints are evaluated using a combination of notch tensile testing and also conventional tensile and fatigue testing. The frictional pressure has a statistically-significant effect on the notch tensile strength of joints produced in all base material combinations. The upset pressure has only a statistically-significant influence on the notch tensile strength properties of alloy 6061/alloy 6061 joints. The notch tensile strengths of MMC/alloy 6061 joints are significantly lower than MMC/MMC and alloy 6061/alloy 6061 joints for all joining parameter settings. The fatigue strength of MMC/MMC joints and alloy 6061/6061 joints are also poorer than the as-received base materials.