Composites of Al-6063 aluminum alloy powder reinforced with graphite particles were prepared by mechanical milling, sintering and subsequent hot extrusion. Mechanical properties and microstructural characterization were done as a function of graphite content. For lower graphite contents mechanical resistance is increasing as the graphite content is increased as well; for higher contents, graphite agglomeration reduces mechanical resistance. This variation is related to the graphite dispersion / agglomeration into aluminum alloy matrix.