Nonorgan-specific autoantibodies (NOSA) are common in patients with chronic hepatitis C virus infection. It is unclear whether serological markers of autoimmunity segregate in a cohort of cases with more severe liver damage. We assessed the relationship between NOSA and demographic, biochemical and histological features in 502 subjects with anti-HCV positive, HCV-RNA positive, HBsAg negative chronic hepatitis consecutively referred to four Italian liver units. Percutaneous liver biopsy was performed in all subjects. A single pathologist scored the biopsies using histology activity index classification. The overall prevalence of positivity for any NOSA was 36.9%. Antinuclear antibodies, anti-smooth muscle antibodies, and anti-liver/kidney microsomal antibodies were found in 15.7, 27.3 and 2.2% of cases. Multivariate analysis showed that gamma-globulin >2 g/dL was the only independent predictor of the likelihood of NOSA positivity (OR, 2.1; 95% CI, 1.3-3.4). No other clinical (age, gender, ALT, HCV genotype) or histological features (grading and staging score, bile ductular damage) were linked to NOSA. Antiviral therapy in 155 subjects with NOSA did not cause any adverse events related to autoimmunity during and after treatment. The presence of NOSA in patients with chronic HCV hepatitis is not related to specific demographic features and has no impact on the biochemical and histological profile of the liver disease at presentation and the response to antiviral treatment.