In this study, we present the findings of a regional retrospective audit of all cases of vulval intraepithelial neoplasia (VIN) diagnosed in Northern Ireland (NI) over an 11-year period (1989-1999). During the period of the study, there were 97 cases of VIN. Cases of VIN were treated by many different clinicians at 14 hospitals. The commonest symptom at presentation was pruritus vulvae. The most common histopathologic diagnosis was VIN III (73%). In 52% of the cases, there was multifocal VIN, and in 43%, there was involvement of other sites such as the cervix, vagina, or anal region. The most common initial treatment was surgical excision, but a multitude of different treatments were performed initially. During the study period, 18 of 90 patients (20%) for whom follow-up was available developed invasive vulval squamous carcinoma. Most of the vulval cancers were superficially invasive, but three patients died of vulval cancer during the study period. This study illustrates that in NI, VIN is treated at many institutions by a multitude of clinicians. Management seems largely dependent on personal clinician preference and has been haphazard with little central coordination and organized strategy. VIN should be managed by clinicians with expertise in this field and who are treating significant numbers of patients according to evidence-based protocols.