LnPO(4)center dot nH(2)O (Ln = La, Ce, Pr, Nd, Sm, Eu and Gd) (n = 0-1) nanowires are synthesized without using any surfactants or templates at room temperature. The as-obtained nanowires are within 10-50 nm in diameter and up to 10 mu m in length. The most important improvement is that the aspect ratios of LnPO(4)center dot nH(2)O nanowires can be effectively controlled by adjusting the reaction time and pH value of the reaction system. The as-synthesized nanowires are characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It is interesting to find that both the inherent crystal structure of light lanthanide phosphate and the anisotropic growth affect the formation of these nanowires. Under the similar reaction conditions, the Eu3+-doped LaPO4 nanomaterials are also synthesized as a comparison. The photoluminescence (PL) instrument is used to investigate the optical properties of the doped nanomaterials. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.