Yttrium aluminum garnet (YAG, Y3Al5O12) was synthesized by sol-gel processing from the stoichiometric amounts of aluminum pellets, Y(NO3)(3).6H(2)O, and Al(NO3)(3).9H(2)O or AlCl3.6H(2)O, with suitable kinds of acid (citric acid, acetic acid, etc.) as catalysts. Poly crystalline YAG powder was obtained by drying the YAG precursor followed by calcination at temperatures above 900degreesC. Thermogravimetry/differential thermal analysis and Fourier transform infrared specotrscopic analyses in air showed an exothermic peak at similar to900degreesC, attributed to the formation of a polycrystalline YAG phase and weight loss of 60% at 1000degreesC, caused by the decomposition of hydroxyl and NO3-, etc. X-ray diffraction analysis showed that YAG can be formed at 900degreesC, and no other intermediate was observed. In particular, the YAG sol can be used for dry-spinning fibers with the aid of some organic polymer.