Soybean sprout decay during its culture should be one of serious problems. The study was carried out to clarify the effect of water imbibition and acetic acid treatments on growth and morphological characters of the soybean sprouts. The soybean seeds of 3 cultivars (cv. Eunhakong, Pungsannamulkong and Junjery) imbibed in pure water or 0.l% acetic acid for 3 minutes before soaked for 6 hours into 1 ppm BA solution and aerated for 3 hours immediately before 6 day culture. On the 6th day, the sprouts were classified into 4 categories on the base of hypocotyl length; > 7cm, 4 to 7cm, > 4cm and not germinated and seed floating rate, their morphological characters, fresh fraction weights and productivity were measured. The best water imbibition for seed cleaning was to soak the seeds for 5 minutes and then to aerate soak them for 40 minutes. In Pungsannamulkong and Junjery, percentage of the sprouts with hypocotyls of longer than 4 cm was higher in water imbibition than in acetic acid treatment for seed disinfection although in Eunhakong there was no significant difference between the two treatments. Eunhakong and Junjery had greater lateral root formation rate and its number per sprout in water imbibition than in acetic acid treatment but Pungsannamulkong showed reverse result. Eunhakong and Pungsannamulkong, furthermore, had more total fresh weight in acetic acid treatment than in water imbibition but Junjery showed reverse result, although there was no significant difference between the two treatments in productivity of mass production system.