In HIV/hepatitis C virus (HCV)-coinfected patients, it is recommended to repeat liver biopsy every 3 years when anti-HCV treatment is not indicated. We studied fibrosis progression in HIV/HCV-coinfected patients, who were not receiving anti-HCV treatment, on the basis of two successive liver biopsies. Thirty-two patients were retrospectively included. Twenty-six patients (79%) were on antiretroviral treatment at the first biopsy. The mean CD4 cell count was 470 +/- 283/mm(3). Three patients were staged F2 and the remainder F0/F1. The median interval between the two biopsies was 49 (24-80) months. At the second biopsy, the stage distribution was F0 0%, F1 41% (n = 13), F2 34% (n = 11), F3 19% (n = 6) and F4 6% (n = 2). The mean fibrosis progression rate (FPR) was 0.25 points/year. Nine patients (28%) were considered as rapid fibrosis progressors (progression by more than two points) and their FPR was 0.5 point/year; comparison of these subjects with the other 23 patients showed no relation between FPR and age, alcohol consumption, CD4+ cell count, HIV viral load, HCV genotype, aspartate aminotransferase or alanine aminotransferase. Analysis of the treatment received between the two liver biopsies did not find any correlation between liver FPR and a specific compound. Fifteen patients started anti-HCV therapy based on the second biopsy. Liver fibrosis in HIV/HCV-coinfected patients should be evaluated at least every 3 years, as nine of 32 (28%) of our patients progressed by at least two fibrosis points despite a high CD4+ cell count. The second biopsy showed that 15 patients (45%) qualified for anti-HCV therapy. Development of noninvasive methods of fibrosis evaluation should permit more frequent monitoring.