Well-crystalline LiFePO4 particles were prepared by a hydrothermal reaction. The particles thus prepared by adding polyethylene glycol (PEG) to the starting reaction solution were fine crystalline in the range of 0.5-1.5 mum with a narrow particle size distribution. The initial discharge capacity of the sample as a lithium secondary battery was achieved to 143 mAhg(-1) at 0.5 mA cm(-2) (corresponding to 35 mA g(-1)) larger than that of the sample prepared by the hydrothermal method without PEG. The increase in the initial discharge capacity should be correlated with the change in particle size and degree of crystallization. (C) 2004 Elsevier B.V. All rights reserved.