Introduction: Invagination is seen rarely as a cause of ileus in adults. The cause of invagination in children differs from that in adults. In adults it is mostly due to organic lesions (tumour). Case report: In a 49 years old patient, with 3 months of intermittant abdominal pain, radiologic investigations suspected a of small bowel tumour. The patient was operated on. At exploration, there was an ileo-ileal invagination on the terminal ileum over 40 cm distance A totally necrosed ileum segment was resected and an end-to-end anastomosis was performed. Inside the excised ileal loop their was a polyp-like lesion originating from submucosa, bordered by the wall but not protruding to the lumen. The pathological examination of the lesion revealed ectopic pancreatic tissue between the muscular layers of the bowel wall. Result: Intestinal invagination must be got in mind as a rare cause of ileus in adults. During it's clinical course their is enough time to reach the diagnosis. So unnecessory resections and postoperative complications can be prevented.