Esophageal dysfunctions occur frequently in patients with diabetic autonomic neuropathy, and the complication of gastroesophageal reflux disease (GERD) has also been reported. However, the characteristics of the GERD complicated with diabetes are obscure, because no detail assessment was performed. We recorded esophageal motility and acid reflux simultaneously in diabetic patients, and the correlation between esophageal dysfunction and diabetic neuropathy was examined. Esophageal dysfunctions including GERD were significantly related to diabetic motor neuropathy. Although the GERD is frequently complicated with diabetes, the symptoms are not apparent in diabetic patients. Therefore, physicians treating diabetic patients should have GERD in mind regardless of the symptoms. We also examined the effect of aldose reductase inhibitor (ARI) on the esophageal dysfunction in diabetic patients. Significant improvement of gastroesophageal reflux and esophageal motility were observed in diabetic patients by ARI treatment. ARI may be useful for the treatment of GERD complicated with diabetes.