Porous ceramics based on refractory double oxides are promising for the next-generation diesel particulate filter (DPF) materials. Similarly to aluminum titanate (Al₂TiO₅), MgTi₂O₅ has a pseudobrookite-type crystal structure with low thermal expansion coefficients among oxides. Since MgTi₂O₅ has higher stability of pseudobrookite phase than Al₂TiO₅, it is expected that MgTi₂O₅-based materials are suitable for the next-generation DPF materials. In this study, porous MgTi₂O₅/MgTiO₃ composites have been prepared by in situ processing (viz. reactive sintering) at 1000–1200°C. Porous MgTi₂O₅/MgTiO₃ composites with very narrow pore-size distribution at the diameter of ∼1 µm were obtained by the pyrolytic reactive sintering at 1000–1100°C. Internal pore-structure was characterized by mercury intrusion–extrusion porosimetry.