OBJECTIVE To analyze the epidemiological risk factors related to clinical and pathological patterns on presentation in patients with chronic hepatitis C (CHC) without cirrhosis. METHODS This prospective study, carried out in the Liver Unit of the Princesa University Hospital, includes a population of 253 patients with CHC without clinical features of cirrhosis evaluated for clinical, virological and histological assessment. A standardized questionnaire was used to identify the presence of risk factors for hepatitis C virus (HCV) infection. Anti-HCV was tested by ELISA-2 and RIBA-2 assays. HCV RNA was analyzed by nested PCR. Liver biopsies were obtained percutaneously or in some cases by laparoscopy. RESULTS The mean age of patients was 43+/-15 years and 154 were males, being significantly younger than females (39+/-13 versus 50+/-14 years). A source of infection was ascertained in 204 (80.6%) patients and only 37 (14.6%) referred a history of acute hepatitis. Anti-HCV was ELISA-2 positive in all 253, and 133 were tested by RIBA-2 (131 positive, 1 negative, 1 indeterminate) and by nested PCR to detect HCV RNA, with positivity in all except 3, including both the RIBA-2 negative and indeterminate. No differences appeared in the histological activity index according to routes of infection, but in comparing sexes, females had a significantly higher total score as well as the inflammatory/hepatitic index and fibrosis. CONCLUSIONS In CHC no epidemiological, clinical or biochemical patterns are indicative of pathological features. The more severe disease in females could be attributed to the fact that they were older and it could be assumed that viral infection progressed longer. This slow progression calls for a therapeutical option over many years.