Background Unregulated commercial blood/plasma collection among farmers occurred between 1992 and 1995 in central China and caused the second major epidemic of human immunodeficiency virus type 1 (HIV-1)infection in China. It is important to characterize HIV-1-infected former blood donors and to study characteristics associated with disease progression for future clinical intervention and vaccine development.Methods A cross-sectional study was performed on HIV-1-infected former blood donors (FBDs) and age-matched HIV-seronegative local residents. Demographic, epidemiologic, clinical and key laboratory data were collected from all study participants. Both unadjusted and adjusted multivariate linear regressions were employed to analyze the association of the decrease of CD4+ T-cell counts with other characteristics.Results Two hundred and ninety-four HIV-1-infected FBDs and 59 age-matched HIV-seronegative local residents were enrolled in this study. The unregulated blood/plasma collection occurred more than a decade (10.8- 12.8 years) ago, which caused the rapid spread of HIV-1 infection and the high prevalence of co-infection with hepatitis C virus (HCV, 89.5%); hepatitis B virus (HBV) co-infection was observed in only 11 HIV+participants (3.7%). Deterioration in both clinical manifestation and laboratory parameters and increase of viral loads were observed in parallel with the decrease of CD4+ T-cell counts. The decrease of total lymphocyte counts (P＜0.001)and hemoglobin levels (P＜0.001) and the appearance of dermatosis (P=0.03) were observed in parallel with the decrease of CD4+ T-cell counts whereas viral loads (P＜0.001) and CD8+ T-cell counts (P=0.01) were inversely associated with CD4+ T-cell counts.Conclusions Co-infection with HCV but not HBV is highly prevalent among HIV-1-infected FBDs. CD4+ T-cell counts is a reliable indicator for disease progression among FBDs. Total lymphocyte counts, hemoglobin level and appearance of dermatosis were positively, whereas CD8+ T-cell counts and viral loads were inversely associated with the decreased CD4+ T-cell counts.