Summary. Liver steatosis, diabetes mellitus and hepatitis C virus (HCV) genotype have been implicated in liver fibrosis in HCV-related chronic active hepatitis (CAH). The aim of this study was to evaluate whether steatosis and diabetes were associated with more severe liver fibrosis in patients with genotype 1b HCV-related CAH. One-hundred and eighty patients (98 men, 82 women; age range 17–68 years; median 51) infected with genotype 1b HCV underwent ultrasound examination and liver biopsy because of elevated levels of serum alanine transaminase. Based on liver histology, patients were divided into three steatosis classes: 1 (involving <33% of hepatocytes), 2 (34–66%) and 3 (>66%). Fibrosis was graded with the Ishak score (range: 0–6). Virological and epidemiologic characteristics, biochemical data, body mass index, and apparent duration of disease were recorded. Diabetes was identified according to American Diabetes Association criteria. The median fibrosis grade was 2 (23 patients had liver cirrhosis) in the three steatosis classes, with no significant differences between classes. At multivariate analysis, fibrosis was significantly related to age, alanine transaminase, diabetes, hepatitis B core antibody, steatohepatitis and grading. At binary logistic regression analysis, only diabetes and fibrosis stage were significantly associated with steatohepatitis. Steatosis was not an independent risk factor for liver disease severity in our CAH/genotype 1b HCV-infected patients. Steatohepatitis was associated as well as diabetes and affected the severity of liver fibrosis.