Meckel's diverticulum is a vestigial remnant of the omphalomesenteric duct. It is the most frequent defect of the gastrointestinal tract and is present in approx. 2% of the population: more often in boys than in girls, at a 3:1 ratio. Meckel's diverticulum causes clinical symptoms only in 4-6% of individuals. It is situated approximately 60-100 cm away from the Bauhin's valve. The wall of Meckel's diverticulum consists of all layers typical of the small intestine. It is usually approx. 2-3 cm long, but it can reach lengths of over 10 centimetres. It is usually set on a narrow base. Related symptoms usually occur by the 2nd-3rd year of life and have an acute character. They may occur in older children, which must be remembered in differential diagnosis. An example can be the case of an 8.5-year-old boy with symptoms indicating obstruction of the gastrointestinal tract in which a large, atypically accreted and partly twisted Meckel's diverticulum was found with strangulation of the small intestine between the diverticulum and the mesentery.