The objective of the present study was to determine the specific activity of the superoxide dismutase enzyme (SOD) in soybeans and soy sprouts. The stability of SOD was also evaluated in stored sprouts, and in recently prepared sprouts exposed to different thermal treatments. The enzymatic activity was determined on crude extracts and those partially purified from whole soybeans, sprouts stored for 10 months at 4°C, and recently prepared sprouts. The latter were also heated to 60, 80, and 100°C for 30 and 60 min. The results suggested that the sprouts had higher amounts of SOD than the beans, and that enzyme activity was not totally lost in stored sprouts, nor in thermally treated sprouts. It was concluded that soy sprouts could be used as antioxidant additives to processed foods prepared by cooking.