Delivery of DNA into intact cells of the developing barley (Hordeum vulgare L.) endosperm was performed with the BIOLISTIC particle gun. It is shown that the proximal 532 base pairs (bp) of the upstream region of a B1-hordein gene drive the expression of the β-glucuronidase (GUS) gene (uidA) in sub-aleurone and starchy-endosperm cells but not in cells devoid of starch, i.e. developing aleurone cells. The 35S promoter from cauliflower mosaic virus was active in all three cell types. This cell-specific activity of the hordein promoter was verified by a detailed histological study of the regions of the extruded endosperms expressing the uidA gene. The analysis included a histological study of the developing endosperm as a base for classifying the different cell types in the developing endosperm.