Large grain UO₂ is a potential fuel for LWR’s for achieving extended burn up. Large grains are obtained by addition of dopants like Nb₂O₅, TiO₂, Cr₂O₃, V₂O₅ etc. However, presence of such dopants might affect the thermophysical and thermomechanical properties of the fuel. In the present investigation the effect of TiO₂ addition on the hot hardness (H) of sintered UO₂ fuel has been studied from ambient to 1573 K in vacuum. TiO₂ content was varied from 0.01 to 0.15 w/o resulting in a grain size (G) variation of 9 to 94 lm. With increase in grain size (or TiO₂ content)H first decreases, attains a minima and then increases further. The increase is more prominent at lower temperature (<773 K) than that at higher temperatures. H vs. G^-1/2 plots indicates the same type of variation like other oxide ceramics with H minima at an intermediate grain size at low temperature. The intrinsic hardness and softening coefficient of UO₂ indicate cubic dependence on TiO₂ content.