Several studies of patients infected with human immunodeficiency virus (HIV) type 1 have suggested that women have lower plasma HIV-1 RNA levels than men, even when controlling for CD4 T cell levels. A cross-sectional analysis was performed in 494 patients (21% of whom were women) who enrolled in a prospective study of anemic HIV-1—infected patients requiring transfusion. The median CD4 T cell count and plasma HIV-1 RNA levels were 15 cells/µL and 4.83 log10 copies/mL (67,350 copies/mL), respectively. In unadjusted analyses, women had slightly higher mean log HIV-1 RNA titers than men (0.19 log10 higher copies/mL; 95% confidence interval, −0.05 to 0.44; P = .11). Adjustment for CD4 T cell count, race or ethnicity, injection drug use, and age yielded a smaller sex difference (0.13 log10 copies/mL higher in women; P = .28). In this population of patients with very advanced HIV disease, there is no evidence that women have lower HIV-1 RNA levels than men.