Effect of iron on the carbothermic reduction of anatase and rutile forms of titanium dioxide was studied. Differential thermogravimetric analysis indicated a significantly different reduction route in the presence of iron with a number of clear minima in the rate of mass loss observed. X-ray diffraction of the products at these minima indicated that rutile initially formed FeTiO 3 which reduced to γ-Ti 3 O 5 , whilst anatase reduced through the mixed Ti(III/IV) phases of general formula Ti n O 2n−1 to d-Ti 3 O 5 . The final stage was the reduction of Ti 3 O 5 to the sub-stoichiometric carbide, TiC 0.5 . Iron was found to stabilise the Ti 3 O 5 phases which were absent from an iron-free system, this is presumed to be due to partial substitution of trivalent iron for trivalent titanium.