CYCLODEXTRIN glucosyl transferase (CGTase) hydrolyses starch to produce â-CYCLODEXTRIN by transglycosylation (cyclization) activity. The conventional method for detection of CGTase activity is based on detecting starch hydrolysis by iodine staining. This method reveals all amylolytic enzymes, but can not discriminate them. In the present study, we introduce a new method for specific detection of CGTase activity and its specific product ie CYCLODEXTRIN by polyacrylamide gel. In this method, solution containing CGTase is subjected to electrophoresis on 10% polyacrylamide gel. Then, the gel is covered with an indicator gel containing PHENOLPHTHALEIN, soluble starch, and agar. After a short incubation, sodium carbonate solution is added and the positive result is indicated by the emergence of a colorless band in the red context of the indicator gel. Since the production of CYCLODEXTRIN via cyclization is unique to CGTase, the emergence of clear bands is indicative of CGTase presence. However, in conventional starch-iodine method, all amylolytic enzymes including CGTase give positive results. Therefore, for detection of CGTase, the PHENOLPHTHALEIN indicator gel method, compared to the starch-iodine method, is more specific.