Genital herpes can be caused by herpes simplex virus 2 (HSV-2) or, less commonly, by herpes simplex virus 1 (HSV-1). With a seroprevalence of antibodies to HSV-2 of 22% in the general population, genital herpes is 1 of the 3 most prevalent sexually transmitted diseases (STDs) in the United States. A central issue in the public health problem of genital herpes is the high proportion of genital HSV infections that are unrecognized by both patients and clinicians. Persons who are HSV-2 seropositive may be symptomatic but nevertheless fail to recognize genital herpes; they serve as reservoirs for transmission. Physicians and patients must be aware of the subclinical presentation of genital herpes and the potential these patients have for transmitting HSV. Serious consequences of HSV infection include neonatal herpes and increased risk of human immunodeficiency virus transmission. Recommendations to physicians for prevention include using type-specific tests for HSV when screening for other STDs and testing for HSV when evaluating patients with genital ulcers. Researchers must evaluate the performance of type-specific tests and strategies to prevent transmission.