In this study, the effect powder size and matrix temperature on the physical and mechanical properties of SiO2-reinforced Al 7075 matrix composites were investigated. It was observed that with increasing powder size and temperature, infiltration height was increased. Optimum parameters of full infiltration that were determined for particle size and temperature were d(50) = 150 mu m and 800 degrees C, respectively. It was also observed that the porosity of the produced composites changed in the range of 3.2-14.6%, and the lowest porosity was obtained from the composite having 105 mu m SiO2 particle size. The highest fracture strength (263 MPa) was obtained from the composite produced at a matrix temperature of 800 degrees C and a particle size of 420 mu m. It was concluded that particle size and temperature are effective parameters to reach full infiltration, and this method is more suitable for producing the composites that have high reinforcement volume fractions than conventional casting methods.