The objective of this study was to estimate the seroprevalence of herpes simplex virus (HSV) types 1 and 2 in male and female soldiers discharged from the Israel Defense Force (IDF) over a period of 18 years. The goal of this study was to study the secular trends of HSV-1 and HSV-2 infection rates in Israeli young adults. Three consecutive cross-sectional studies were carried out on stored sera of systematic random samples of soldiers (median age = 20.8) discharged from the IDF in 1984-1985, 1992-1993, and 2001-2002. HSV-1 and -2 seroprevalence was analyzed using indirect IgG enzyme-linked immunosorbent assay for type-specific antibodies. There was a significant decrease in HSV-1 and HSV-2 seropositivity rates at discharge from the army and an estimated 10-fold decline in the incidence rates of HSV-2 infection during the military service over the last 2 decades. The decline in HSV-1 seroprevalence rate is similar to that reported from other industrialized countries. The decrease in HSV-2 seroprevalence and transmission rates among Israeli young adults is steeper than that reported from Western countries.