BACKGROUND AND OBJECTIVE: The aim of this study was to measure contemporaneously HCV-RNA load, HIV-RNA load and CD4+ lymphocyte count in HCV/HIV coinfected patients with coagulopathy and to examine the relationship between these parameters and the liver failure. DESIGN AND METHODS: A cross-sectional study was performed on 54 patients with severe coagulopathy: 39 HCV/HIV coinfected and 15 HCV+/HIV- comparable for age and HCV exposure time. HCV-RNA and HIV-RNA load, CD4+ lymphocyte count, biochemical and ultrasonographic parameters were evaluated at the time of entry to the study. RESULTS: Mean HCV-RNA load was significantly higher in coinfected patients (643,872 717,687 copies/mL) than in HCV+/HIV- (mean 161,573 276,896 copies/mL) (p = 0.01). The 39 HCV/HIV coinfected patients had a mean HIV-RNA load of 205,913 456,311 copies/mL (range 4,000-2,500,000) and a mean CD4+ lymphocyte count of 206.5171/microL (range 5-693). Five of the 39 (12.8%) coinfected patients had liver failure. In these five patients the mean HCV-RNA load (770,200 996,426 copies/mL) was high but not significantly different from that in the 34 HCV+/HIV+ patients (623,496 682,239 copies/mL) without liver failure (p = 1.0). Coinfected patients with liver failure had a significantly higher HIV-RNA load (mean 764, 599 978,542 copies/mL) and lower CD4+ lymphocyte count (mean 52.655. 6/microL) than those observed in coinfected patients without liver failure (p = 0.007 and p = 0.03, respectively). A significant inverse correlation was found between CD4+ lymphocyte count and HIV-RNA load (r = -0.37, p = 0.01). INTERPRETATION AND CONCLUSIONS: HCV-RNA load is significantly higher in HIV+ than in HIV- patients with coagulopathy. Liver failure was found only in the HCV/HIV coinfected patients with severe immunodepression, expressed either by low CD4+ lymphocyte count or by high HIV-RNA load.