A case of a primary amelanotic melanoma of the vagina is reported. The patient was a 58-year-old Japanese female. A polypoid tumor was found on the lateral wall of the vagina and a cytologic examination of a scraping showed a few large atypical cells with cleaved nuclei and intranuclear vacuoles. A lateral junctional spread was histologically observed and stage II melanosomes were found in the cytoplasm. Two years after a radical operation, the patient died of a widespread melanotic metastases. The authors survey the number of incidences of malignant melanoma in the female genital organ. In Japanese women, melanoma is seen more frequently in the vagina than in the vulva, which is quite the opposite in cases of malignant melanomas of the genital organs in women of the United States and Europe.