A pilot study of cervical cytology was carried out on 500 new patients at the women's sexually transmitted disease (STD) clinic at this hospital. The aim was to discover the incidence of abnormal smears in order to gauge the worth of cervical cytology as a routine clinic procedure. Information was also gathered on each patient's age, sexual history, method of contraception used, previous smears, and genital infection. Smears showing carcinoma in situ, dysplasia, or warty atypia were regarded as abnormal, and the relevant patients were referred for colposcopy. Seventy-three (14.6%) had abnormal smears. Eight women (1.6%), average age 29.7 years, had cervical intraepithelial neoplasia grade III (CIN III) confirmed by histology. One third of the patients with abnormal smears had genital warts, and the incidence of abnormal smears was greater in patients with genital warts than in those without warts. We concluded that STD clinics are useful places in which to carry out cervical cytology screening, and we noted a positive association between infection with genital warts and abnormal smears.