It is rare to find three separate primary cancers in one individual. But, multiple primary cancers have been increasing because of improved methods of diagnosis and treatment and greater longevity of the population. We experienced a 52-year old male patient with synchronous triple primary adenocarcinomas occurring at the duodenum, right colon and sigmoid colon, who complained of abdominal pain and hematochezia for 2 months. The patient underwent pancreaticoduodenectomy, right hemicolectomy, and anterior resection, and was recovered uneventfully. After surgery, postoperative adjuvant chemotherapy (5-FU and Leucovorin) is currently being administered.