A cohort of 103 human immunodeficiency virus type 1 (HIV-1)-infected persons with well-defined dates of seroconversion were studied to determine whether baseline plasma HIV RNA loads 6–12 months after seroconversion have prognostic value. Baseline plasma virus loads had predictive value for the disease-free survival rate and for the survival rate. The level of baseline HIV RNA also had a strong negative predictive value for the CD4+ T cell count during the fifth year of infection: A baseline load > 5 log was predictive of a CD4+ T cell count < 500/mm3 5 years after infection. Baseline HIV RNA load was a CD4+ T cell-independent predictor of progression to death. The major finding was that the disease outcome for HIV-1-infected persons is already determined during the first year of infection.