In this study, TiO2 nanowires with diameter of 20–23 nm was successfully synthesized using treatment of TiO2 nanoparticle with concentrated sodium hydroxide at 150 °C for 6 hours. The dielectric properties of bulk TiO2 nanoparticle, anatase TiO2 nanowires (annealed at 500 °C) and rutile TiO2 (annealed at 900 °C) was investigated. The crystallographic phase of TiO2 was determined using X-ray diffraction (XRD). The morphology of the samples was observed by Field emission scanning electron microscopy (FESEM). The dielectric constant and the dielectric losses at room temperature were measured in the frequency range of 1Hz–1MHz. The dielectric constant of bulk TiO2 nanoparticles, anatase TiO2 nanowires and rutile TiO2 nanowires measured at 1Hz were 50, 50 and 356, respectively.