A possible hepatotoxicity of cigarette smoke has been recently suggested by epidemiological and experimental studies. Our aim was to study the possible relationships between smoking and liver fibrosis and activity in patients with chronic hepatitis C. A cross-sectional study was performed in a group of 310 patients with chronic hepatitis C consecutively hospitalized for their first liver biopsy. The relationships between age, gender, alcohol consumption, route of contamination, tobacco consumption, and Knodell fibrosis and activity scores were examined in univariate, age-adjusted, and multivariate analyses. One hundred and seventy-six patients (57%) were current smokers. Smokers were younger (P <.001), more often of male gender (P =.001), more often alcohol consumers (P =.001), and more often had a history of intravenous drug use (P =.0001) than never smokers. Smoking was related to increased fibrosis and activity scores in age-adjusted (P =.009 and P =.005, respectively) and multivariate analyses (P =.03 and P =.04, respectively). Smoking increases the severity of hepatic lesions in patients with chronic hepatitis C.