Primary vaginal adenocarcinoma of intestinal type is a rare malignant gynecologic disease. A 53-year-old woman was admitted to our institution with a diagnosis of endometrial adenocarcinoma. A physical examination revealed a 2-cm polypoid lesion of the vagina. The patient underwent surgery for endometrial cancer and wedge resection of the vaginal lesion. The diagnosis of primary vaginal adenocarcinoma of intestinal type was obtained after standard and immunohistochemical analyses of the specimen. No endometrial cancer was detected in the specimen. Radiological investigations excluded metastasis from the gastrointestinal tract. Subsequently, the patient underwent concomitant chemoradiation. At present, 32 months later, she is well and disease-free. Extensive radiological investigations and careful immunohistochemical analysis of the specimen are needed for a correct diagnosis of vaginal adenocarcinoma of intestinal type. Concomitant chemoradiation, as a primary treatment, should be considered.