The aim of the current study was to investigate the histological and histochemical characteristics of large and small intestines of sea snake, Hydrophis cyanocinctus. Six adult sea snakes were collected from Minab beaches, located near the sea of Oman, in November, euthanized with chloroform, dissected and alimentary canal removed, tissues preparaed for sectioning and staining with Hematoxylin and Eosin (H&E) and Periodic Acid Schiff's (PAS) methods, and observed with a light microscope equipped with a dinolite lens. Histological evaluation showed that the walls of each organ was formed of mucosa, submucosa, muscularis and serosa. The wall of the small intestine has numerous circular folds with zigzag patterns. Epithelium of small intestine is composed of simple long columnar and goblet PAS positive cells. The epithelial layer of large intestine was formed of long simple columnar cells with acidophilic cytoplasm. Also, PAS positive goblet cells were found scattered in epithelial tissue. In histometry, the epithelial length and width in primary of small intestine was larger than other parts. Goblet cells with 15.36 ± 1.12 were more frequent in the large intestine. Thickness of both internal and external muscular layers were the most at the end of small intestine (p ≤ 0.05).
