Primary adenocarcinoma of the rectovaginal septum is an extremely rare disease and have been reported only twenty cases all over the world, and that considered arise from endometriosis in most of the cases. We report two cases, 53-year-old and 48-year-old women, of primary adenocarcinoma of the rectovaginal septum without endometriosis. This tumor is important to consider one of the pelvic tumors. We discuss the clinical findings, examination findings and pathogenesis of this tumor.