The effects of soymilk residues solubilization by cellulase, protease, koji and yeast were investigated on dry matter and protein yields, amino acid and organic acid contents. Co-treatment of soymilk residues by cellulase and protease gave high dry matter yield and protein yield. Koji treatment followed by yeast fermentation was effective for increasing organic acid content and producing soy sauce-like taste and odor. Organic acid content of fermented hydrolysates was improved by cellulase treatment. Protease treatment rather than koji treatment gave high amino acid content, and cellulase treatment seemed to have little effect on increasing free amino acid content. In sensory evaluation, koji-treated hydrolysate showed higher overall acceptance than other hydrolysates, however it showed lower overall acceptance than commercial fermented soy sauce.