Nanocrystalline LiMn2O4 spinel was synthesized by a sol-gel method using citric acid as a chelating agent, at the calcination temperature of 600degreesC for 10h. The as-prepared LiMn2O4 was investigated by a variety of techniques, including X-ray powder diffraction, transmission electron microscopy (TEM), and X-ray photoelectron spectra. TEM images indicated that the average crystallite size is about 40 nm with a fairly narrow size-distribution. Results showed that the calcination temperature and the calcination time played significant roles in the formation of nanocrystalline LiMn2O4. A possible mechanism on the formation of the nanocrystallites was also discussed. (C) 2003 Elsevier Science B.V. All rights reserved.