Intussusception is defined as the invagination of one part of the gastrointestinal tract into another. Jejunogastric intussusception is a rare phenomenon following major upper abdominal surgery, where its aetiology is not well understood. We describe a 68-year-old woman who presented with abdominal pain and haematemesis on the background of a previous pancreaticoduodenectomy (Whipple procedure) for pancreatic cancer. Gastroscopy demonstrated retrograde jejunogastric intussusception, where part of the efferent jejunal limb had prolapsed into the remnant stomach. As a consequence, this intussuscepted segment had become oedematous and ischaemic. The patient subsequently underwent a laparotomy, where the original gastrojejunostomy was resected, which showed the intussuscepted jejunum. The non-viable portion was removed and a Roux-en-Y anastomosis was created. This case highlights the need to ‘think outside the box’ with respect to differential diagnoses when a patient presents with abdominal pain on the background of previous complex abdominal surgery.