This article discuss the effects of heat treatment on the machinability of Al-Si-Mg alloys (A356) cast alloys for as-received alloy, solution heat-treated alloy (SHT) as well as solution heat treated and then aged alloys at 155ºC, 180ºC, and 220ºC. In the course of machinability evaluation, several criteria including cutting force, surface roughness, tool wears and burr analysis (chip) were studied. The results and analysis in this work indicated that selected machinability criteria are important and necessary to effectively evaluate the machinability of A356 alloys. Machinability of both materials and tool was estimated in terms of chip thickness ratio and burr formation, roughness, cutting force and flank wear. The effects of various lubrication modes such as dry, mist and wet, cutting parameters, including cutting speed and feed rate on the machinability of A356 cast alloys were also examined. Experimental results proves that the heat treatment parameters strongly controlling the burr formation and surface quality. The results obtained indicate that better drilling performance in terms of surface quality occurs at high feed rate, dry drilling and artificial aging at T6.