Aluminum matrix composites have a long history and they are still in the focus of interest. Molten metal processes are basic and the most common techniques of these kind of materials. Using lost foam casting process (LFCP) for aluminum matrix composite production is a new approach. LFCP is a special casting method, and it has flexibilities and advantages under complexity, material, and production aspects. It was considered that, reinforcement materials (SiC particles, etc) can be added to molten aluminum within the expanded polystyrene (EPS) foam patterns. Successful experiments were performed; SiC particles and molten aluminum were mixed with lost foam casting (LFC) technique. And this current study was carried out to determine the mechanical properties of A6063/SiC cast composites. The microstructures of the castings were investigated with optical and scanning electron microscopy (SEM). Archimedes density test, tensile, impact, and Brinell hardness tests were performed, and the results are consistent to those generally observed for metal matrix composites. Hardness, especially yield strength of matrix was increased with reinforcement addition, however ductility and toughness were decreased. Also, the respective production technique has a significant effect on the mechanical properties.