The present work derives defect diagrams for titanium dioxide, TiO 2 , within a wide range of oxygen partial pressures involving the n-type regime, the p-type regime and the n-p transition regime in the range 973-1373K. The non-stoichiometry and related defect disorder of TiO 2 are considered in terms of defects in both sub-lattices involving:Oxygen sublattice: oxygen vacanciesTi sublattice: Ti vacancies and Ti interstitialsDefect diagrams are derived in terms of defects concentration (oxygen vacancies, tri- and four-valent Ti interstitials) as a function of oxygen partial pressure) at different levels of acceptor- and donor-type pre-imposed defects (Ti vacancies and foreign cations).