11 cases of intussusception in adults, including 9 treated by operation, are discussed. The cause of the intussusception was a malignant lesion in 7 and a benign lesion in 2 cases. In 2 patients, reposition was achieved with the aid of a barium enema. Aetiology and clinical and radiological features are discussed. In view of the high incidence of pre-existent lesions and the risk of perforation at reposition with the aid of a barium enema, surgical therapy is indicated. The pre-existent lesions found at operation and pathological anatomical examination were: malignant lymphoma (4 cases), caecal adenocarcinoma (2 cases), leiomyofibroma of the ileum (1 case), caecal endometriosis (1 case), carcinoid appendix (1 case) and Meckel's diverticulum (2 cases).