The present study was conducted to study the endocrine portion of the pancreas represented by Islets of Langerhans in the adult males and females guinea pigs. Eight animals of each sex were collected to conduct these aims. Histological sections prepared from the specimens which were collected from three identified lobes of the pancreas and subsequently fixed by 10% neutral buffered formalin. Post conducting the routine histological procedure on specimens, three stains were used such as hematoxylin and eosin, Masson's trichrome and Gomori's Aldehyde trichrome for identification of cellular composition of the pancreatic Islet's of Langerhans.
        The endocrine islets showed predominantly ß, and for a lesser extent α cells. The δ cells were rarely detected. The percentage of ß cells in the islets of male pancreas was higher than those in females. On contrary, the percentage of α cells was higher in the islets of females than those in the males. Such findings were proportional to hormones analysis of insulin and glucagon which were corresponding products to these cells. In conclusion, Percentage of ß cells in the islets of male pancreas was higher than that in females. On the contrary, the percentage of α cells was higher in the islets of females than that in the males. Such observations were parallel positively with hormones analysis of insulin and glucagon which were corresponding products to these cells.