We have optimized the composition of a mixture of aluminum yttrium hydroxynitrates, urea, and acetic acid for the self-propagating high-temperature synthesis of yttrium aluminum garnet (YAG) powder. The powder prepared in this way offers a low degree of agglomeration, and the ceramic produced from it has a low carbon content. A technique has been proposed for carbon determination in YAG ceramics through gas chromatographic analysis of the gaseous products of carbide hydrolysis after the dissolution of the ceramic in pyrophosphoric acid.