We report herein an unusual case of metachronous triple cancers of the sigmoid colon, stomach, and esophagus. A 60-year-old man was initially admitted to our hospital for investigation of occult fecal blood. This was found to be caused by sigmoid colon cancer which was resected in July 1985 (T3, N0, M0; Stage II). A follow-up endoscopy performed in 1990 showed early gastric cancer, and a gastrectomy was performed in August 1990 (Tis, N0, M0; Stage 0). Another endoscopic examination performed as follow-up in 1993 revealed early cancer of the remnant stomach, and all the remnant stomach was surgically resected in March 1993 (Tis, N0, M0; Stage 0). He presented again in December 1996, complaining of discomfort in the chest which was found to be caused by cancer of the middle thoracic esophagus. Although surgery was considered necessary, the patient refused to undergo any further operations. Instead, radiation was administered from January 1997. An endoscopy after the completion of radiotherapy confirmed that the cancer had almost disappeared; however, it started to grow again from the beginning of 1998. He was hospitalized due to esophageal stenosis in April 1998, and died of carcinomatous cachexia in September of the same year.