Cysts of the ileocecal region constitute a definite pathologic and surgical entity. That they are enterogenous developmental cysts, there can be no doubt. While the nature of these cysts is now well understood, the cause of their origin remains obscure. In many of the lower animals, the arrangement of the cecal pouches is suggestive. Ileocecal cysts are rare. A search of the literature yielded but twenty cases. It is evident, however, that many cases have been overlooked. With a growing appreciation of the condition, one may expect a marked increase in the number of cases reported. Cysts and diverticula of the intestine apparently escaped the notice of the older pathologists. In the small intestine, diverticula and cysts are found between the leaves of the mesentery, where the vessels pierce the wall of the intestine, leaving a point of lessened resistance. In the large intestine the mucosal hernias or diverticula escape