This study was undertaken to investigate the effect of different concentrations of Yttrium (0.1, 0.3, 0.5, 1.0 wt.%) and heat treatment on the microstructure, hardness and wear resistance of an in-situ cast composite (Al-15%Mg2Si ). The microstructural study of the composite before and after solution and ageing showed both primary and secondary Mg2Si phases in all specimens and intermetallics containing Y (Al2Y) were visible after Solution at 520 °C for 4 hours. Hardness measurement demonstrates that the addition of Y increases the hardness gradually but a reduction in the hardness of heat treated specimen’s occurs with the addition of Y ( 0.5%Y).Wear tests were performed using a pin on disk apparatus. The MMCs were rubbed against a carbon steel pin under a load of 10 and 20 N at a sliding velocity of 0.1 ms−1; track length of 1500 m. The degree of improvement in dry sliding wear resistance brought about by Y addition is strongly dependent on the formation of Yttrium rich intermetallic phases as well as heat treatment influence and the wear behavior determined through the precise measurement of weight loss of the samples and wear rates. Worn surfaces were analyzed by scanning electron microscopy (SEM).