BACKGROUND:?An intussusception is the invagination of one segment of the intestine into another. It is more common in children, but a rare clinical entity in adults, where the condition is almost always caused by tumors. METHODS:?A 51-year-old female presented with symptoms of gastric outlet obstruction associated with signiifcant weight loss, but no jaundice. Routine hematological and biochemical investigation, including tumor markers, were normal. Abdominal ultrasound revealed duodenojejunal intussusception, and subsequent CT of the abdomen conifrmed it. RESULTS:?She underwent a laparotomy, which conifrmed duodenojejunal intussusception. On reducing the intussusception and performing a duodenotomy, a periampullary mass was conifrmed. Hence, she underwent a pylorus-preserving pancreaticoduodenectomy. Histology conifrmed periampullary adenocarcinoma. CONCLUSIONS:?Adult intussusceptions are mostly caused by tumors. Contrast CT is the investigation of choice, although ultrasound can be used. One should have a low threshold for suspecting malignancy, obtain frozen section histology, and seek appropriate help at an early stage.