The research is carried on cardiac glands region of the abomasum of the bull by both descriptive and cytochemical ultrastructure. The propose is to compare the present results on this gastric zone to those previously obtained in the other zones of bovine abomasum and the few data referred by other workers in monogastrics. The endocrine cells (Diffuse Neuroendocrine System) identified are in type and order of frequency: EC, ECL, X, D, D1 and these results correspond to those of the proper gastric glands region in the same species. In addition, their lack in luminal connection and their peculiar relationship with the parietal cells is similar in the two zones. On the other hand, a full comparison with monogastrics is not yet possible because analogous studies on the cardiac glands of other species are sparse.