Uniform rod-like ultrafine powders of Bi2S3 with a diameter of 40 nm and a length of up to 150 nm have been successfully prepared by the hydrothermal treatment of an alkaline sol (pH = 8.0-10.0) from BiCl3 and Na2S . 9H(2)O with EDTA as complexing agent at relatively low temperature. Powder X-ray diffraction (XRD) pattern indicated that the product was pure orthorhombic Bi2S3 phase with cell constants a = 11.138, b = 11.290, and c = 3.980 Angstrom. The optimum condition for crystallization of amorphous Bi2S3 is hydrothermal treatment at 100-150 degrees C for 6 to 12 h. The X-ray photoelectron spectra and infrared (IR) spectra confirmed that the product was of high purity,