INTRODUCTION: Genital herpes (GH) is the most common cause of genital ulceration, but is not reportable in Canada. Research in the United States has found that less than 10% of seropositive persons reported a diagnosis of GH. The present article investigates the rates of diagnosed cases of GH in Canada from 2002 to 2007.METHODS: Primary case diagnosis data on GH for the period between 2002 and 2007 were obtained from the Canadian Disease and Therapeutic Index, a proprietary database maintained by Intercontinental Medical Statistics (IMS) Health Canada. Of the 45,000 to 49,000 office-based physicians in Canada, IMS Health collected diagnosis-specific prescription diaries from a sample of 652, stratified according to geographic region and representing all major specialties, during this period.RESULTS: Between 2002 and 2007, there were approximately 84,398 to 122,456 medically attended GH cases annually in Canada. Approximately 74% to 93% of these diagnosed cases made one physician visit per year. The annual rate of medically attended GH cases ranged from 261.2 per 100,000 population to 386.6 per 100,000 population.DISCUSSION: The present report is the first time that administrative data have been used to estimate the annual rate of medically attended GH cases in Canada. The data include both incident and prevalent cases and are likely an underestimate of the actual number of cases because they only represent diagnosed cases presenting for medical care. Further seroepidemiological and clinical research studies would be helpful to assess the burden of infection and to plan appropriate diagnostic, treatment and preventive counselling services.