7 new cases of cysts in the mesentery of the small bowel are presented, together with 54 clinically and histologically well documented cases from the literature. Most cysts are found in laparotomy for an acute abdomen. Almost half of the patients are under the age of 11 years. The cysts can be unilocular, multilocular or multiple. Cysts in the mesentery of the jejunum always had a chylous content. Most often the wall consists of an endothelial lining, smooth muscle, lymphatic tissue and lymphatic vessels. Inflammation and/or bleeding destroyed the endothelial lining and added granulation tissue to the histologic picture. With the exception of 7 cases, the cysts are probably of congenital and lymphatic origin. Trauma, infection, bleeding or volvulus can make a silent cyst manifest.