Magnesia-graphite refractory materials are used in large quantities in the steelmaking process. The chemical characterization of this type of refractories is an arduous task that requires a rigorous set of laboratory tests and analyses. In the present paper, proper characterization of magnesia-graphite refractories has been approached by X-ray powder diffraction combined with Rietveld methodology. The quantitative phase analysis of a MgO-graphite refractory has been 68.3wt% of MgO, 8.1wt% of graphite, 13.5wt% of Al 2 O 3 , 4.4wt% of SiC, 0.6wt% of Si, 1.2wt% of Al, 1.5wt% of AlPO 4 and 2.4wt% of silicone. These results have been checked and validated with those obtained by other analysis procedures used to determine the crystalline and non-crystalline phases present in these materials.