Objectives To document the frequency of pathology in women who complain of postcoital bleeding. To determine whether negative cervical cytology excludes serious pathology in women with postcoital bleeding. To determine whether postcoital bleeding increases the risk of serious pathology in women with an abnormal smear. Design A retrospective study. Setting A university teaching hospital. Population 314 women with postcoital bleeding seen in the gynaecology service from first January 1988 to 31 December 1994, Methods women were identified from the computerised records of the colposcopy sen;ice and copies of correspondence, which was routinely retained on computer. The latter was searched for the text strings coital and intercourse. Main outcome measure Histopathological diagnosis. Results Twelve women (4%) had invasive cancer: 10 were cervical or vaginal cancers and two endometrial cancers. Eight of the 10 cervical or vaginal cancers were clinically apparent, Four women of these 10 had had a normal smear before being referred for further investigation of postcoital bleeding. Two of these cancers were visible only with the aid of the colposcope. Thus, 0.6% of women attending a gynaecology service with postcoital bleeding, a normal looking cervix and a normal smear had invasive cancer of the cervix. Cervical intraepithelial neoplasia were found in 54 women (17.%) and 15 women (5%) had cervical polyps. Nineteen of the 63 women (30%) with significant pathology had a normal or inflammatory cervical smear. No explanation for the postcoital bleeding was found in 155 women (49%). Conclusions Although invasive cancer is rare in women with postcoital bleeding, it is much commoner than in the general population. It seems likely that cervical intraepithelial neoplasia is also associated with postcoital bleeding, perhaps because the fragile cervical epithelium becomes detached during intercourse. Postcoital bleeding should continue to be regarded as an indication of high risk for invasive cervical cancer and for cervical intraepithelial neoplasia. Prompt referral to a colposcopy clinic is indicated, but most women with postcoital bleeding will have no serious abnormality