Meckels Diverticulum is the most common congenital anomaly of GI tract. Complications develop in about 4% of cases as an acute abdomen. During the last 12 years, 58 patients with Meckel's diverticulum were treated in Amir-Kabir children's hospital. The majority of our cases (84%, 49 from 58) were under 6 years of age, with boys outnumbering girls (4:1). Intestinal obstruction was the most common form of presentation, included 60% of symptomatic patients and lower GI bleeding was the second one and included 25% of symptomatic cases. 31% (18 cases) were found in laparotomy for other reasons (Asymptomatic). There were heterotopic gastric mucosa in all of 10 patients with lower GI bleeding out in 4 of 18 incidentally discovered cases. In conclusion the Meckel's diverticulum must be one of the primary concern, in the differential diagnosis of the pediatric patients with painless, moderate to massive rectal bleeding with or without clots, intestinal obstruction or abdominal pain of uncertain cause. Heterotopic tissue in Meckel's diverticulum has important role in occurrence of complications.