A cohort of 79 homosexual men with documented dates of human immunodeficiency virus type 1 (HIV-1) seroconversion and baseline CD4 cell counts of ⩾500/µL were followed for up to 11.5 years. HIV-1 RNA was measured from stored sera obtained a median of 7 months after the estimated seroconversion date. AIDS progression and mortality among the men were studied, stratified by median baseline levels of HIV-1 RNA. AIDS progression rates at 11.5 years were 69% and 34%, respectively, among those with higher versus lower than median baseline virus loads (⩾3040 copies/mL; P = .002), and mortality rates were 61% and 27%, respectively (P = .003). Survival curves continued to diverge throughout the 11.5 years, suggesting that the future clinical course of HIV-1 infection may already be determined at the earliest phases of disease. Initiation of definitive treatment very early in HIV-1 infection may be essential.