Occurrence rates and determinants of infection with herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) were measured in first- and fourth-year undergraduate students at a state university. This cross-sectional multistage probability sample survey included sociodemographic characteristics, sexual behavior patterns, disease history, and HSV type-specific antibody status. The prevalence of HSV-1 antibody was 37.2% in freshmen and 46.1% in fourth-year students; that for HSV-2 antibody was 0.4% and 4.3%, respectively. A history of cold sores was obtained in 25.6% of the freshmen; none had a history of manifest genital herpes. A history of cold sores was obtained in 28% and a history of genital herpes in 1.1% of the fourth-year students. The case-weighted prevalence of HSV-1 and HSV-2 antibodies was found to be significantly elevated for a number of student characteristics. However, multiple logistic regression analyses indicated that the significant predictors of HSV-1 antibodies in this population were female gender, black race, first intercourse at age less than or equal to 15 years, total years of sexual activity, history of a partner with oral sores, and a personal history of a non-HSV sexually transmitted disease (STD). Predictors of HSV-2 antibody were black race, duration of sexual activity, and history of a non-HSV STD.