One hundred and ninety-eight patients with abnormal cytologic smears had extensive diagnostic biopsy of the portio combined with endocervical curettage. Severe dysplasia or cancer in situ was found in 57 per cent of the patients. During a period of observation of 6--42 months (average 18 months) the cervical intraepithelial neoplasia (CIN) regressed in 54 per cent. Cryosurgery was used to treat 93 patients with persistent CIN after biopsy. Treatment was successful in almost 70 per cent after one single application of cryosurgery. The complications were negligible. Treatment was less successful with increasing histological severity as well as with increasing age of the patients; this applies both to biopsy and cryosurgery. Cryosurgery is significantly less effective when the CIN is of both ecto- and endocervical origin. Extensive multiple biopsies of the portio in combination with endocervical curettage performed under general anaesthesia, followed by cryosurgery with persistent cytological abnormalities, are indicated as an alternative to conization, especially in younger patients with ectocervical CIN.