Yogurt with high levels of gamma-aminobutyric acid (GABA), free amino acids and isoflavones was developed using lactic acid bacteria (LAB) and germinated soybean extract. Fermented soya milk (GABA soya yogurt) produced with starter and substrate had the GABA concentration of 424.67 mu g/g DW, whereas fermented milk produced by a conventional method had GABA less than 1.5 mu g/g DW. The GABA soya yogurt also contained significantly high levels of free amino acids and isoflavones compared with other conventional yogurts. The results suggested that the Lactobacillus brevis OPY-1 and germinated soybean possessed a prospect to be applied in dairy and other health products with high nutritive values and functional properties. (c) 2006 Elsevier Ltd. All rights reserved.