To evaluate the incidence of underlying serious gynaecological pathology in women referred to colposcopy with post-coital bleeding.Incidence of precancer and cancer.A retrospective cohort study of women referred to colposcopy at a London hospital from January 2008-March 2015. Inclusion criteria are women with post-coital bleeding and the following cervical cytology history: negative; inadequate; never had. Multinomial logistic regression was used to assess for significant risk factors for cervical dysplasia and cancer.Overall, 635 women with either negative cytology (n = 436/68.7%), no previous cytology (n = 175/27.6%), or inadequate cytology (n = 24/3.8%) were referred to colposcopy for post-coital bleeding. The median age is 35 years (S.D. = 9.7 years). In 256 (40.3%) women, no cause was detected, and 322 (50.7%) women had a benign cause. Overall, 42 (6.6%) women had low-grade dysplasia, and eleven women had high-grade dysplasia (1.7%). Four women (0.6%) had cervical cancer; clinically evident cancer on speculum examination (n = 3); micro-invasive cancer (n = 1). Current smokers were significantly more likely to have HPV atypia (p = 0.015) or cervical intraepithelial neoplasm grade 1 (CIN1) p = 0.003. Advancing age was a significant risk factor for cervical cancer (p = 0.037).All women with post-coital bleeding need an urgent speculum examination to rule out frank cervical cancer. Although most women had a benign cause for post-coital bleeding, around 2% had a colposcopy-aided diagnosis of either cervical precancer or cancer; therefore, referral of symptomatic women deserves consideration. HPV testing may reduce referrals to colposcopy for post-coital bleeding due to non-significant pathology in the future.