Histology is the process of anatomical study of tissue sections or cells. Histology of ileum segment of small intestine reveals that it is composed of four layer of gastrointestinal system, namely, lumen, mucosa, sub mucosa, mascularis. Ileum is characterized by the presence of large number Peyer's patches, unencapsulated lymphoid nodules containing cells of the immune system and presence of more fat inside the mesentery than the jejunum. Edited by Ashraf