In this study, corrosion behaviours of MgO-C refractories produced by the incorporation of carbon and pyrolytic carbon black obtained from waste tire pyrolysis under either argon or oxygen atmospheres were investigated. Moreover, the effect of porosity on the corrosion resistance of those refractories was studied. The microstructures of corroded refractories were characterized by Scanning Electron Microscopy (SEM)/EDX. Experimental studies indicated that refractories produced by the use of pyrolytic carbon black as a carbon source had higher amount of porosity due to their lower packing density and lower corrosion resistance than those of ones produced by the incorporation of graphite.