The diagnostic verification of Pap III and Pap III D-smears from mass screening is described with special regard to the importance of colposcopical and cytological long-term controls. 233 (59.8%) out of 390 patients were verified within one year (1.1.-31.12. 1977). A high percentage (27.5%) of the first control smears was negative or the cytological picture had become normal (19.5%) after vaginal treatment by antibiotics and application of estrogens. 50 women were cured by conization or primary hysterectomy as the cytological diagnosis yielded suspicion of severe dysplasia or carcinoma in situ. Depending on cytological differential diagnosis, individual situations and the developmental tendency of the atypical epithelium 157 patients (40.2%) were observed for several years. The great diagnostical-therapeutical importance of colposcopy for the early recognition of cervical intraepithelial neoplasia (CIN) is demonstrated. A direct microbiopsy controlled by colposcopy is a valuable completing method if there are differences between colposcopical and cytological findings during a long-term control of the cases. A slight or moderate dysplasia can be observed for about 2 or 3 years, as most regressions are seen in this period. In problematic cases (young nullipare, patients treated because of infertility or sterility, pregnant women, old women) with severe dysplasia/carcinoma in situ it is possible and justifiable to control the patient temporarily in short distances. All cases which are suspicious of an early stromal invasion call for a definite diagnosis and therapy without any delay. Primary hysterectomy is preferred in patients aged 35 years or more.