The present study was conducted to determine the effects on the growth, feed conversion, and body composition of fermented defatted soybean meal (SBM) either with Aspergillus oryzae or Eurotium repens in single moist pellet diets for juvenile yellowtail Seriola quinqueradiata. The growth and feed efficiency of fish fed on the fermented SBM diets were superior to those fed on an unfermented SBM diet, but they were slightly inferior to those fed on a high fish meal diet without SBM. There were no marked differences in the body or blood components between any of the groups. Though neither of the fermentations of SBM with fungi affected POV, trypsin inhibitor activity, or amino acid composition, both treatments similarly increased low molecular weight-proteins and decreased oligosaccharides, resulting in higher digestibilities of dietary protein and carbohydrate. These improved digestibilities through fermentation of SBM might contribute to better growth performance in the fish.