A 41-year-old woman presented with irregular vaginal bleeding, and a vaginal tumor was found and proved to be a clear cell carcinoma by biopsy. An F-FDG PET/CT was performed to exclude its metastatic possibility, which showed the vaginal tumor was the only lesion with F-FDG avidity. The vaginectomy and hysterectomy were performed to resect the lesion, and primary clear cell carcinoma of the vagina was finally diagnosed.