[en] The phase equilibria in the Fe-Mo-Ti system at 1,000 C have been studied using the diffusion couple technique. The various phases formed during annealing at 1,000 C for 480 hours were examined by X-ray diffraction, and no new ternary phase was observed. The equilibrium compositions of these phases and some tie-lines were measured by means of electron probe microanalysis. The results show that the solubility of Mo in the λ phase Fe₂Ti ranges from 0 to 25.03 at. pct following the formula Fe₂(Mo,Ti) and solubility of Ti in the μ phase ranges from 0 to 14.55 at. pct following Fe₇(Mo,Ti)₆, whereas the solubility of Mo in the FeTi phase is negligible. It is expected that Fe₂Mo and Fe₂Ti can form a complete series of solid solutions below 900 C. On the basis of the sublattice models, the thermodynamic properties of the Fe-Mo-Ti system at 1,000 C have been evaluated from the present results. An isothermal section calculated at 1,000 C is presented, and it shows good agreement with the experiments