Multiple primary cancer is defined as the multiple occurrence of malignant neoplasm in the same individual. Synchronous cancers are usually defined as finding the second cancer at the same time or within a 6-month period after the diagnosis of the primary lesion, and metachronous cancers are found at more than 6 months after the initial diagnosis. Multiple primary cancers have been increasing reported on due to prolonged lifespans and the improvement of diagnostic techniques. Nevertheless, triple synchronous cancers have been regarded as a relatively rare finding. We report here on an unusual case of triple synchronous cancer of early gastric cancer, carcinoid tumor of the ampulla of Vater and renal cell carcinoma. (Korean J Gastrointest Endosc 2006;32:136 140)