A 75-year-old woman who had been healthy except for mild glycemia and lipidemia discovered three and a half months before admission experienced severe dysphagia secondary to oral and esophageal candidiasis. She eventually developed diabetic hyperosmolar syndrome and ketoacidosis. Since anti-GAD antibody was negative and her diabetes was controlled with a moderate dose of insulin, we made a diagnosis of type 2 diabetes. Her only risk factors for candidiasis were hyperglycemia, age, and continuous denture use. The fact that her diabetes developed in association with oral candidiasis supports the hypothesis that there is a bidirectional interrelationship between diabetes and oral infection.