Cryosurgery was used to treat 208 patients with cervical intraepithelial neoplasia. These patients were referred to our Colposcopy Clinic for investigation of an abnormal Papanicolaou smear. Prior to treatment a colposcopically directed biopsy was taken in all cases. The regrigerant used for cryosurgery was nitrous oxide. Included in the 208 patients were 57 with mild dysplasia, 76 with moderate dysplasia, 44 with severe dysplasia and 31 with carcinoma in situ. The cure rates were 100 per cent for patients with mild dysplasia, 95 per cent for those with moderate dysplasia, 96 per cent for those with severe dysplasia and 91 per cent for those with carcinoma in situ. Cryosurgery is an effective method of treating cervical intraepithelial neoplasia, with cures obtained in 199 of 208 patients in this study.