In this paper, the effect of manganese (wt%) and size of the Al2O3 abrasive grains of abrasive wear behaviours of Al-Si-(0.16-0.76%) Mn alloy was examined. Abrasive wear experiments were conducted against abrasive Al2O3 paper grains with diameters in the variety of 38-250 mu m, under the normal load range of 10, 20 and 30 N and the sliding velocity of 0.1 m s(-1). Wear measurements have shown that the wear rate of the material is dependent on the manganese content and the abrasive grain size. The best wear resistance is in the content of 0.73 Mn, which is associated with increased toughness and strength. The Al-Si casting alloy which had 0.73% Mn content exhibited lower wear rate than the Al-Si-0.16/0.22/0.23% Mn alloys after scoured on fine abrasive Al2O3 grains (<65 mu m). Wear experiments achieved on Al2O3 grains having sizes greater than 65 mu m revealed that, the cast Al-Si- alloy which had 0.73% Mn content had lower wear rate than the cast Al-Si-0.16/0.22/0.23% Mn alloys.