Reports suggest that jejunal pouch interposition (JPI) after proximal gastrectomy is superior in terms of food intake volume and prevention of reflux esophagitis early after surgery. However, the long-term results and late complications of the procedure are not well known. This case report describes an excessive pouch dilatation necessitating surgical intervention as a late complication of JPI. The patient was a 62-year-old woman with early gastric cancer who underwent proximal gastrectomy. Gastrointestinal continuity was restored with JPI. The patient’s postoperative course was uneventful and follow-up imaging studies showed no signs of tumor recurrence. However, the patient gradually started to experience difficulty eating food and complained of postprandial nausea and vomiting. Contrast radiography of the upper gastrointestinal tract revealed a dilated jejunal pouch, which eventually required surgical intervention. The jejunal pouch and remnant stomach were resected, followed by Roux-en-Y reconstruction. The postoperative course was uneventful and the symptoms subsided. The present case highlights the importance of a clinical study focusing on the long-term results of this surgical procedure.