Magnesium aluminate spinel was synthesized by solid oxide reaction route at 1400  C and then added to magnesia refractory brick compositions in the range of 0–30 weight percentages. Optimum firing temperature of the magnesia–spinel refractory composites was determined from densification study and phase analysis. Final refractory products were then characterized by thermal expansion, refractoriness under load, cold strength, retainment of cold strength after thermal shock, hot strength at different temperatures and micro-structural analysis. Spinel (20 wt.%) containing magnesia composition was found to have superior properties.