The sintering and microstructure development of magnesia containing 0-10wt% TiO2 at temperatures in the range 1300-1600 degrees C have been investigated. The addition of TiO2 markedly promoted densification at relatively low temperature, and grain growth. Excess TiO2 over the solid solubility limit of TiO2 (0.3 wt%) reacted with magnesia to form inter- and intra-granular magnesium titanate (Mg2TiO4) above 1300 degrees C. The grain size of MgO increased with increasing TiO2 content, and densification was mainly governed by MgO grain growth.