Congenital diaphragmatic hernia is a rare condition in adulthood. It is even more exceptional when located on the right side. We describe a case of right-sided congenital diaphragmatic hernia in a 74-year old woman. The diagnosis was only made when the patient developed an acute intestinal obstruction after a laparotomy for a gynaecological benign tumour. The treatment of this condition is discussed. In our opinion, in elderly, the advantages of an elective operation in asymptomatic congenital diaphragmatic hernia have to outweigh the risks of the operation. However, if the patient shows symptoms of pulmonary dysfunction or motility disorders of the gut, or even when he has to undergo a laparotomy for a different reason, we advise to repair the hernia in order to prevent complications.