Radish root is a rich source of amylase. In the present investigation detection of amylase activity, progression of degradation of starch by amylase, and certain factors which affect radish amylase activity have been studied. The factors that have been studied are the effects of enzyme concentration, pH and temperature. The iodine reagent test and the dinitrosalicylic acid (DNS) reagent method have been used. Using the iodine reagent test the progression of degradation of starch was studied colorimetrically. The increase in the amount of sugars as a result of amylase action on starch has been shown colorimetrically using the DNS reagent method. The results show that young radish roots are richer in amylase than full-grown roots. As the enzyme concentration was increased the time taken to reach the end point decreased, and the amount of sugars formed increased up to a certain concentration. The optimal pH for radish amylase was 6.2. Interestingly, the amylase was stable up to 90oC. In fact, both the iodine reagent test and the DNS reagent method showed that the enzyme activity was far more at 50o to 90oC as compared to 31oC. When the effect of temperature on amylase activity was studied by the DNS reagent method it was observed that the enzyme activity increased as the temperature was increased from 33oC (room temperature) to 50oC; surprisingly the amylase activity increased slightly at 60oC when compared to the activity at 50oC, and at 90oC when compared to the activity at 60oC. The results show that radish amylase is thermostable.