This study investigated the 5-year follow-up status of women with cervical smears showing borderline nuclear changes (BNC) or mild dyskaryosis and the effect of koilocytosis on the outcome. Thirteen per cent of women with cervical smears showing BNC had high-grade cervical intraepithelial neoplasia (CIN). In contrast, 28% of women with cervical smears showing mild dyskaryosis had high-grade CIN. The presence of koilocytosis (24% for borderline smears and 34% for mild dyskaryotic smears) did not appear to influence the risk of developing high-grade CIN. Our results suggest that the simultaneous implementation of the British Society for Clinical Cytology proposed terminology and the colposcopy guidelines from the British Society for Colposcopy and Cervical Pathology could have an impact on colposcopy services.