Amylase activity has been studied in disks of hypocotyl of Phaseolus vulgaris L. Although some activity is present in untreated hypocotyls, it is greatly increased when disks are incubated 4 days in water containing kinetin (5 mg/liter). Gibberellic acid and 2,4-dichlorophenoxyacetic acid do not increase this activity appreciably. The increased activity can be shown by subsequently incubating the disks on starch agar plates and testing these with iodine-potassium iodide solution, or by using the original incubation medium and extracts of the disks in reactions with soluble starch. A variety of tests favor the assumption that the enzyme is alpha-amylase and that it is synthesized during the incubation period.