Human immunodeficiency virus (HIV) type 1 RNA loads were determined for 256 subjects with early (incident) HIV infection and for 1293 subjects with later (prevalent) HIV infection, in a Ugandan cohort. Prevalent infections were classified as latent (0-1 symptoms) and midstage disease (>/=2 symptoms), and deaths were ascribed to acquired immunodeficiency syndrome. Among subjects with incident HIV infection, HIV load did not differ by sex, but, among subjects with prevalent HIV infection, it was higher in males than in females. HIV load was highest in subjects (25-29 years old) with incident HIV infection but increased with age in subjects with prevalent HIV infection. Viremia was higher after serconversion than in latency and increased with more advanced disease. Viremia was increased with genital ulcer disease (GUD) in both subjects with incident infection and in those with prevalent infection, and with herpes simplex virus type 2 seropositivity in subjects with incident HIV infection. GUD was consistently associated with higher HIV loads in subjects with incident and those with prevalent HIV infection, suggesting that treatment of GUD might reduce HIV viremia.