Cronkhite-Canada Syndrome (CCS) is a rare non-inherited gastrointestinal polyposis syndrome with characteristic ectodermal changes. We report an extremely unusual case of CCS associated with primary esophageal and gastric cancers. A 74-year-old Japanese man with symptoms of anorexia and diarrhea was found to have primary esophageal and gastric cancers, as well as multiple gastric and colonic polyps. Based on the physical findings of onychodystrophy and alopecia, we diagnosed CCS. Because of his age and nutritional status, we decided to perform total gastrectomy for gastric cancer and chemoradiotherapy for esophageal cancer, upon completion of which the patient was started on steroid therapy for the CCS. After 1 week of steroid therapy, the patient's watery diarrhea improved. We recommend that for patients with CCS, the therapeutic strategy be carefully considered based on the patient's nutritional status, the severity of the CCS, and the extent of gastrointestinal cancer.