This study was carried out to investigate the effect of carbonated water on the yield, weight, length, thickness, and vitamin C and isoflavone contents of soybean sprouts cultivated for 6 days. 100 g Junjori cultivar soybeans were cultivated at $22{pm}1^{circ}C$ with carbonated water (pH 4.5) and drinking water (pH 7.8) for 6 days, respectively, after 6h presoaking treatment. The yield of the soybean sprouts cultivated with carbonated water for 6 days was 255.1 g, approximately 1.45 times higher than the 176.1 g soybean sprouts cultivated in drinking water. The weight and length of the soybean sprouts cultivated with carbonated water were 1.3 and 1.2 times higher, respectively, than those of the soybean sprouts cultivated with drinking water. The same can be said of the thickness of the carbonated- and drinking-water soybean sprouts. The vitamin C contents of the soybean sprouts cultivated with carbonated water was about two times (1.13 mg%) higher than those of the soybean sprouts cultivated with drinking water. The genistein and daidzeinin contents of the soybean sprouts cultivated for 6 days with carbonated water were higher than those of the soybean sprouts cultivated for 6 days with drinking water. The growth characteristics and contents of the useful components of the soybean sprouts were affected more by carbonated water than by drinking water.