There is an increasing tendency of a so-called conservative treatment of intraepithelial atypia. The new term of cervical intraepithelial neoplasia (CIN) supposedly called for a new concept of treatment. However, the term CIN replaces only the ambiguous terms of Carcinoma in situ and Dysplasia. The term CIN expresses the latter two being principally identical changes that are distinguishable only by differentiation. Persistent dysplasia is nothing but a highly differentiated Carcinoma in situ and must be treated as such. - For final diagnosis of CIN not only the histological pattern must be known but above all the relationship to the stroma and the extent of changes. NEither cytology nor colposcopy and directed biopsy or a combination of these can define the lesions with such accuracy as is necessary as a basis for a really adequate treatment. It could be proved that treatment results of Carcinoma in situ depended on the quality of primary diagnosis. Out of 390 cases that were treated after limited biopsy, eight died of cancer. After treatment of 1012 cases with conization alone there was not one fatal case. The danger of so-called conservative treatment lies not only in unrecognized invasive lesions but above all in preinvasive lesions remaining in deeply situated glands. Their discovery may fail in spite of regular follow-ups. They will reappear possibly only after a long latency period as invasive cancer.