Meckel's diverticulum, an omphalomesenteric remnant caused by the failure of the vitelline duct to involute by the seventh or eight week of gestation, was first described in 1809 by Johann Friederick Meckel. It is the most common congenital abnormality of the small intestine. It is usually located in the last 90 cm of the terminal ileum and is formed by all layers of the small intestine. It frequently contains heterotopic tissue, usually gastric mucosa. Here we report a 15-year-old white female who presented to the emergency ward with abdominal pain. Laparatomy was performed with the diagnosis of acute abdomen. A Meckel's diverticulum was found in the mesenteric aspect of the ileum. Histologic examination of the specimen revealed the presence of pancreatic tissue and oxyntic and antral type gastric mucosa showing chronic peptic ulceration apart from intestinal mucosa.This case report underlines the need for a revision in our understanding and classification of Meckel's diverticulum.