High-quality rutile TiO₂ nanocrystals have been synthesized by a simple hydrothermal treatment of a watersoluble titanium–glycolate complex at 200°C. The obtained samples were composed of rod- or whisker-like nanocrystals. The aspect ratios of these nanocrystals could be controlled by adding glycolic acid. Combined characterizations with X-ray diffraction, Raman scattering and high-resolution transmission electron microscopy revealed the formation of highly phase-pure and well-crystallized rutile nanorods/nanowhiskers with the c-axis orientation. Room-temperature dielectric measurements indicated that the permittivity for the rutile nanowhiskers is ~150 at 100 kHz, which is higher than that for the bulk rutile powder. These observations pave a way for morphological controlled rutile nanocrytals to find a broad class of technological uses.