Gynecological cytology has been intensified in the district of Schwerin since 1968. The incidence of cervical carcinoma decreased from 38.9 per 100,000 women in 1969 to 19.8 in 1991 (50% of the initial figure). The mortality decreased from 25.1 to as little as 7.0 (28% of the initial figure). Because invasive cervical carcinoma is theoretically avoidable, a total of 577 new cases observed from 1980 to 1988 were investigated in respect of participation in screening and reasons for the failures. 317 (55%) of these women did not participate in the examination more than five years before diagnosis of invasive cancer. 260 (45%) of these women were examined by gynecologists once, several times (87 (67%)) or annually (173 (33%)) during a five year period prior to the diagnosis of cancer. An independent review of the smears explained the highest number of negative smears by nonobtaining of representative material and only 19% as a ministerpretation of the cytological finding. The gynecologists failed to: take smears (36 women); carry out a cytological control or histological verification (48); obtain adequate smears (116); consider clinical symptoms (22).