HIV infection is believed to adversely affect the progression of hepatitis C virus (HCV)-related liver disease. However, information regarding HIV and HCV coinfection in the era of highly active antiretroviral therapy (HAART) is scarce. A cross-sectional study in 75 HCV/HIV-coinfected patients (most of them on HAART) and 75 HCV-monoinfected patients paired by age, sex, and date of liver biopsy analyzed the association of HIV infection with advanced liver fibrosis (Knodell fibrosis stages 3 + 4). The median CD4 cell count in HIV-coinfected patients was 546 cells/microl; 78.7% had an HIV-1 viral load <1000 copies/ml and 88% were on antiretroviral therapy. The percentage of patients harboring genotype 4 and with a higher HCV viral load was greater in the HIV-coinfected group. HCV/HIV-coinfected patients had more advanced liver fibrosis (Knodell fibrosis stages 3 + 4) than HCV-monoinfected patients (46.7% vs. 12%, p < 0.0001). In the univariate analysis, the factors associated with advanced liver disease were male sex (OR: 2.7, 95% CI: 1.05-7.1), history of injecting drug use (OR: 4.6, 95% CI: 2.0-10.2), HIV infection (OR: 6.4, 95% CI: 2.7-14.7), and previous exposure to therapy with protease inhibitors (OR: 3.0, 95% CI:1.4-6.3). In the multivariate analysis; only male sex (OR: 3.17, 95% CI: 1.152-8.773) and HIV infection (OR: 6.85, 95% CI: 2.93-16.005) were associated with advanced liver fibrosis. HIV infection is associated with advanced liver fibrosis. HIV/HCV-coinfected individuals on HAART are at risk of developing end-stage liver disease despite virological success and immunological reconstitution.