This chapter reviews the contribution of cervical cytology, what makes it successful, the management of screen positives and how technological advances may affect its use in the future. Cervical screening has saved hundreds of thousands of lives but has not been available to women in the poorest countries. In countries where wide coverage has been achieved and quality assurance is in place, incidence and death rates have fallen by over 50% even though cervical cytology is logistically complex. The management of high-grade cervical intraepithelial neoplasia (CIN) is very effective, but low-grade cytological abnormalities require care to avoid over-treatment. The increasing rate of human papillomavirus (HPV) testing and the prospect of prophylactic vaccination will change the way cervical cytology is used, possibly giving way to HPV testing as the primary test in secondary prevention.