Bi20TiO32 in the form of nanocones are reported for the first time, which have been found during the formation of Bi2TiO7 nanocrystals. Bi20TiO32 nanocones were prepared by metalorganic decomposition technique. From X-ray patterns, it was found that Bi20TiO32 is a metastable phase, and can transform gradually into Bi2Ti2O7 phase with the annealing time increasing at a temperature of 550degreesC. The image of field emission scanning electron microscopy shows that the lengths of the nanocones are up to several micrometers and the diameters of cusps range from 20 to 200 nm. The studies of transmission electron microscopy show that the nanocones are crystalline Bi20TiO32. The growth mechanism of Bi20TiO32 nanocones has been proposed, which is similar to the vapor-liquid-solid growth mechanism. (C) 2002 Elsevier Science B.V. All rights reserved.