Abstract: The present invention provides for the expression of phytase in transgenic plants or plant organs and methods for the production of such plants. DNA expression constructs are provided for the transformation of plants with a gene encoding phytase under the control of regulatory sequences which are capable of directing the expression of phytase. These regulatory sequences include sequences capable of directing transcription in plants, either constitutively, or stage and/or tissue specific, depending on the use of the plant or parts thereof. The transgenic plants and plant organs provided by the present invention may be applied to a variety of industrial processes either directly, e.g. in animal feeds or alternatively, the expressed phytase may be extracted and if desired, purified before application.