Amyloglucosidase (E.C. 3.2.1.3) was entrapped into reverse micelles of Triton X-100-xylene-hexanol. The observed activity in reverse micelles was influenced by the water content. Activity was studied at different water-surfactant ratios (Wo) and pH. The effects of Wo, glycerol and temperature on stability were analysed. Amyloglucosidase was active in the above mentioned system, although the overall activity was lower than in the aqueous system, it showed higher stability in reverse micelles up to 50 degrees C. (C) 2000 Elsevier Science Ltd. All rights reserved.