The present paper describes the processing of an Si-Ti-C-O fabric/mullite powder/polytitanocarbosilane composite and the mechanical properties of the densified composite. A polytitanocarbosilane (a precursor of Si-Ti-C-O fabric, 20-30 mass%)/xylene solution was infiltrated into a laminated porous mullite composite with 22similar to36 vol% fabric and thermally decomposed to an amorphous solid at 10000degreesC, in an argon atmosphere, to decrease the porosity. The decrease in porosity of the composite with pyrolysis of the precursor polymer was compared with the theoretically-calculated porosity. The infiltration/pyrolysis process was repeated eight times to produce composites of 80similar to85% theoretical density. The prepared composites showed a nonlinear increase of stress up to 0.7similar to1.0% of tensile strain and fractured in the strength range from 102 to 265 MPa. The analysis of the apparent Young's modulus, tensile strength and fracture energy concludes that (1) the strength is dominated by the product of the effective fabric content, the Young's modulus of the filament and elongation of the composite and (2) the fracture energy of the composite is greatly affected by the tensile strength because of the similar elongation at fracture.