The endocrine cells of the stomach and duodenum of the pond tortoise (Amyda sinensis) have been studied by electron microscopy. At least six types of endocrine cells could be identified in these regions. Type I cells were characterized by having pleomorphic or medium sized granules ($100{sim}430nm$ in diameter, mean; 290 nm) which were moderate in electron density. Type II cells were characterized by having pleomorphic or medium sized granules ($190{sim}430nm$ in diameter, mean; 280 nm) which were high in electron density. Type III cells were characterized by having large oval or irregular granules($170{sim}650nm$, mean: 430 nm) with wide vesicular halo which were high in electron density. Type IV cells were characterized by having round or medium sized granules($140{sim}370nm$, mean; 240 nm) which were low to moderate in electron density and showed a very thin halo. Type V cells were characterized by having large round or oval granules($300{sim}600nm$, mean; 410 nm) which were low to moderate in electron density and showed a dense core and a wide clear halo. Microfilaments were also found in the cytoplasm. Type VI cells were characterized by having round and small granules($100{sim}220nm$, mean; 160 nm) which were low to moderate in electron density and showed a very thin halo or crystalline structure of the contents. Many microfilament bundles were also found in the cytoplasm.