The compositions of Fe‐Ti‐O melts in equilibrium with molten iron have been determined by melting mixtures of TiO2, metallic iron and various additions of either Fe2O3 or metallic titanium in a high‐frequency induction furnace. The furnace had a vertically segmented water‐cooled copper crucible which enabled the mixture to be melted with vigorous stirring inside a freeze‐lining of about 1 mm thickness. The slag compositions were found to form a curved line in the ternary diagram FeTiO3 – TiO2 – Ti2O3 with its highest TiO2 content slightly higher than the pseudobrookite (M3O5) composition FeTi2O5 ‐ Ti3O5. The slags were examined by X‐ray diffraction and microprobe analyses. For all slags the main phase was pseudobrookite (M3O5) solid solution with some rutile or Magnéli phase (TinO2n‐1). The most iron‐rich and the most titanium‐rich slags contained also some FeTiO3, respectively Ti2O3 phase. A melting point diagram is suggested with a eutectic groove running between the M3O5 phase and the TiO2 or Magnéli phase from about 1665°C for the iron‐free to the less than 1500°C for the titanium‐free slags.