Histological parameters were assessed in liver biopsies (n = 48) performed in patients co-infected with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) and/or hepatitis C virus (HCV) in order to evaluate factors which were associated with significant liver disease. Necroinflammation and fibrosis was scored by the Ishak classification system, and binary logistic regression analysis was used to assess HIV and antiretroviral-related determinants of necroinflammation and fibrosis. A total of 46 biopsies were included; 33 were from HIV-positive patients co-infected with HCV and 15 biopsies were from HIV-positive patients co-infected with HBV. One HIV-positive patient was co-infected with HBV and HCV. Median biopsy inflammatory grade for the cohort was 8.5 (IQR 6-10), the median fibrosis Stage 2 (IQR 1.8-4), and the median steatosis score was 1 (IQR 0-2). At the univariate level, HIV-related variables that were significantly associated with more severe biopsy changes were higher HIV RNA at the time of biopsy (associated with inflammatory Grade 10+; P = 0.018) and any exposure to didanasine (ddI) or stavudine (D4T; associated with fibrosis Stage 3+; P = 0.022). HIV RNA at the time of biopsy remained significant at the multivariate level. Patients with HIV hepatitis co-infection in this cohort had surprisingly mild changes in liver histology, and there were no statistically significant differences between biopsy results in HBV compared to HCV co-infection. The association between HIV RNA and necroinflammation supports current recommendations for earlier initiation of HAART in patients with HIV-hepatitis co-infection. J. Med. Virol. 84: 993-1001, 2012. © 2012 Wiley Periodicals, Inc.