Detection of tumour cells in cervicovaginal secretions nearly always indicates the presence of a malignant tumour or epithelial dysplasia. Presence of suspicious cells or cells with atypical nuclei very often suggests the existence of a malignant tumour or epithelial dysplasia (46 and 14%, respectively). The great majority of the remaining patients with such cytological changes suffer from other gynaecological diseases, most often of an inflammatory nature. A cytologic differentiation between these groups is not yet possible. Other examinations are therefore indicated. Cytological changes in the cervicovaginal secretion rise in frequency with increasing age. In 9% of the patients with carcinoma of the cervix no abnormal cells were detected in the cervicovaginal secretions. The corresponding figures for severe (“carcinoma in situ”) and moderately severe epithelial atypia were 22 and 31%, respectively. No more than one third of the patients with carcinoma of the uterine body had abnormal cytology. Hence, on the slightest suspicion of malignancy we should not rely on a “negative cytology”, and especially not as the result of a single examination. Carcinomas of the uterine body generally manifest themselves by bleeding disorders. The diagnosis is to be established on the basis of curettage. In the present series the cytologic examination decided the diagnosis and treatment in no more than a single case of cervical carcinoma. Cytologic examination therefore seems to be of limited value for patients admitted to a gynaecological unit, where other diagnostic aids are available. On the other hand, the method is believed to be of value in practice, when we bear in mind that, like other methods, it is vitiated by a certain margin of error. On the slightest clinical suspicion of a malignant or premalignant disease we should not rest content with a single negative examination.