The incidence of multiple primary malignancy is extremely rare although the prevalence rate is increasing recently. There are several reasons of increment of multiple primary malignancy. First, the advances in the treatment and the diagnostic modality of malignancy have led to increased survival rate. So many of the patients who survived the first cancer could live long enough to develop additional primary cancers. Second, the long term effects of chemotherapy and radiation therapy have been proved oncogenic. Third, increasing age, environmental carcinogen, some kinds of viral infection, and genetic predisposition have potentials for multiple carcinogenesis. Most of multiple primary cancer is double primary, however triple primary cancer is rare. We experienced a case of triple primary cancer involving endometrium, colon, and stomach. We report this case with a review of literatures.