A hybrid polymer as the precursor for TiO₂/SiO₂ composite fibers was prepared by blending polycarbosilane (PCS) and tetrabutyl titanate, named as PCST, which contains unreacted organic tetrabutyl titanate compound. The PCST was characterized by FT-IR, TGA and NMR (¹H, ¹³C and ²⁹Si). The results showed that the PCST could be described as a part dispersion of Ti(OC₄H₉)₄ groups in the PCS chain matrix. The TiO₂/SiO₂ composite fibers were manufactured by melt-spinning PCST, maturing and curing the resulting fibers in air, followed by a final pyrolysis at 1200 °C in air. Based on the XRD, EPMA, EDS, SEM and HRTEM measurements, the TiO₂/SiO₂ fibers were made up of anatase-TiO₂ nanocrystallites with a mean size of ∼10 nm and in the amorphous silica phase.