Lithium niobate powders from the raw powders of Li2CO3 and Nb2O5 are directly synthesized by a combustion method with urea as fuel. The synthesis parameters (e.g., the calcination temperature, calcination time, and urea-to-(Li2CO3 + Nb2O5) quantity ratio) are studied to reveal the optimized synthesis conditions for preparing high-quality lithium niobate powders. In our present work, it is found that a urea-to(Li2CO3+Nb2O5) ratio close to 3, calcination temperature at 550 similar to 600 degrees C and reaction time around 2.5 h may lead to high-quality lithium niobate powders. The microstructure of synthesized powders is further studied; a possible mechanism of the involved reactions is also proposed. (c) 2005 Elsevier B.V. All rights reserved.