Congenital mesenteric defects are rare and often recognized only in surgery or autopsy. Preoperative diagnosis of an internal hernia is quite rare. A common symptom of trans-mesenteric intestinal herniation is intermittent postprandial pain. If there is strangulation of the mesenteric internal herniation, there is often vomiting and constipation. Signs and symptoms of a bowel obstruction in a patient without previous abdominal surgery or inguinal hernia as well as without history of intra-abdominal operation and infection suggest the possibility of a congenital mesenteric defect with internal herniation. Early diagnosis and surgical treatment are important to reduce morbidity and mortality. This study aimed to present the case of a 20-year-old female patient on whom preoperative diagnosis of internal trans-mesenteric internal hernia was made.