This research was carried on 10 apparent healthy adult ballady ducks (Anas platyrhynchos) of both sexes with average age ranged from (6-7) months and average weight ranged from (4.5- 5.5) Kg. Small pieces from longitudinal section of pyloric region were fixed immediately in 10% neutral buffered formalin solution and Bouin's fixatives, processed, stained with Delafield's iron heamatoxylin and eosin (H&E), Masson's trichrome, Periodic acid Schiff (PAS), Alcian blue pH 1, Alcian blue pH 2.5, combined PAS-Alcian blue pH 2.5, Aldehyde fuchsin and Best's carmine stains. In addition, small pieces (1mm) from pyloric region were fixed in paraformaldehyde-glutraldehyde in phosphate buffer and were examined with transmission electron microscope. The pyloric region was a third part of the stomach, it was very small area between the gizzard and duodenum. The mucous membrane of the pyloric region was lined by simple columnar mucous secreting epithelium.The lamina propria contained solitary lymph nodules; supported by smooth muscle fibers of the muscularis mucosa. The surface epithelium displayed strong reaction to PAS, moderate reaction to Alcian blue pH 1, Alcian blue pH 2.5 and Best's carmine stains. Ultrastructurally, five cell types could be observed in the pyloric region;surface epithelial mucous cells, chief,
intermediate, basal and enteroendocrine cells. The mucous cells contained round electron dense granules. In addition to the presence of circular mitochondria were found in the cytoplasm in close association with the rough endoplasmic reticulum (rER). Chief cell contained well-developed rER in the perinuclear area, numerous round mitochondria and few electron dense granules. In the intermediate type, perinuclear rER was observed. Basal cells had few cisternae of rER. However, five types of enteroendocrine cells were identified according to their shape, size of their granules and internal structure.