An intussusception of the small intestine in association with a long tube usually occurs in the vicinity of the mercury-filled bag and can be visualized radiographically by instilling barium directly into the tube. On rare occasions, an intussusception develops in the proximal jejunum and is difficult to recognize. We report the fifth and sixth cases of a proximal jejunal intussusception with a long tube in situ and outline a clinical approach that facilitates a prompt, accurate diagnosis. A proximal jejunal intussusception should be suspected if copious bilious vomiting and abdominal pain occur following intubation of the small intestine with a long tube.