['Visits to physicians for genital herpes simplex virus (HSV) infection continue to increase. Most patients with symptomatic infections have recurrences, but no studies of the long-term clinical course of genital herpes are available.', 'To determine whether the frequency of HSV recurrences decreases over time.', 'Observational cohort study.', 'University-based research clinic.', '664 persons with genital herpes followed for at least 14 months.', 'Patients were classified as having initial or recurrent HSV-1 or HSV-2 infection. Patient-reported recurrences and observed recurrences were recorded in a database; more than 12,000 recurrences were analyzed.', 'Median recurrence rates in the first year of follow-up were one and five per year in patients with newly acquired HSV-1 and HSV-2 infection, respectively; second-year rates were significantly lower in both groups. Patients presenting with recurrent HSV-2 infection had higher rates of recurrence in the first and second years and no significant decrease; significant decreases were detected with longer follow-up. One third of all patients experienced a decrease of two or more recurrences per year between years 1 and 2. Patients infected with HSV-2 who were followed for more than 4 years had a median decrease of two recurrences between years 1 and 5. However, 25% of these patients had an increase of at least one recurrence in year 5, illustrating the variability among HSV-infected persons. Decreases over time among patients who never received suppressive therapy were similar to decreases during untreated periods in patients who received suppressive therapy.'] Does clinical reactivation of genital herpes simplex virus infection decrease in frequency over time?