The natural history of initial and subsequent recurrent herpes simplex virus (HSV) genital infection was studied in guinea pigs immunized with HSV glycoprotein vaccines before vaginal challenge with HSV-2. The vaccines used included HSV-1 glycoprotein Band HSV-1 glycoprotein D, both prepared by recombinant DNA techniques, and mixtures of HSV-1 or HSV-2 glycoproteins, prepared from infected cell monolayers by lectin chromotography. Immunizing guinea pigs with subunit HSV glycoprotein vaccines favorably altered the clinical and virological course of initial infection and substantially reduced the incidence, frequency, and duration of recurrent herpetic infections. The extent of protection was influenced by the nature of the glycoprotein vaccine, the immunizing dose, and the co-administration of adjuvant.