This paper reports on buried bumper syndrome that is an early complication of percutaneous endoscopic gastrostomy. The patient, a 69-year-old woman with impaired conversation due to Alzheimer's disease, was unable to swallow safely. She had undergone percutaneous endoscopic gastrostomy in the standard manner, and it had allowed her to be cared for in her own home. The patient's family had followed the instructions accompanying the device without difficulty until 5 days before presentation, when they noticed leakage around the tube. On examination, the stoma site was reddish, and at endoscopy, we were unable to confirm the internal bumper. Instead, there was a raised mound and a central small round concave area of gastric mucosa without ulceration and edema. Fluid under pressure could not be injected through the percutaneous endoscopic gastrostomy tube. The internal bumper had become embedded in the anterior abdominal wall. In this case, the first percutaneous endoscopic gastrostomy was removed with incision of abdominal wall under local anesthesia for a short period, and a second percutaneous endoscopic gastrostomy was created, without difficulty. Therefore, we should take greater care when we carry out percutaneous endoscopic gastrostomy in patients with dementia and without paralysis of the upper extremities.