Persisting dysplasias are nothing but carcinomas in situ with special differentiation. As such they become directly invasive and are differently located as classical carcinomas in situ. Intraepithelial lesions arise in clearly defined fields and do not spread into neighbouring epithelia. Most lesions are located within the cervical mucosa and less frequent in the region of original squamous epithelium. Treatment must be based on the knowledge of changes being truly intraepithelial and upon their extent. When primarily extirpating the uterus such knowledge is not available. Of 160 cases of primary hysterectomy two patients died of cancer. Vaginal hysterectomy produced better results than the abdominal. Electrocoagulation, cryosurgery and laser treatment destroy lesions without exact knowledge of their extent. Conisation combined with careful sectioning of specimen gives the best survey of the lesions. Of 1 219 conisation cases conisation was the only therapy in 918 patients. None of these died of cancer.