AIM: To determine effectiveness of treatment for hepatitis C outside clinical trials, by testing the hypothesis that apparent effectiveness and tolerability of interferon alfa-2b/ribavirin combination therapy would be less in a hospital liver clinic setting. DESIGN: Retrospective analysis of all patients in one centre commencing interferon alfa-2b/ribavirin therapy, but not in clinical trials, between 1998 and 2000. MAIN OUTCOME MEASURES: Effectiveness as sustained virological response (SVR); tolerability as premature discontinuation of treatment. RESULTS: The 121 patients had similar demographic and viral characteristics as those in Australian trials (age, 44 +/- 10 years; males, 66%; genotype 1, 44%; genotype 3, 36%), but 38% had advanced fibrosis, including 17% with cirrhosis. Sixty (50%) were previously untreated, 38 (31%) had relapsed after initial response (response relapse) and 23 (19%) were non-responders to interferon monotherapy. Sustained viral response (SVR) was achieved in 53% of patients overall: 47% of patients with genotype 1 HCV, 71% of patients with genotype 3. For patients with genotype 1 HCV, SVR was 43% in those previously untreated, 63% in response relapsers, and 38% in non-responders. Corresponding SVRs for genotype 3 were 65%, 87% and 33%. These results are similar to those obtained in published trials. Only 7% of our patients discontinued treatment because of adverse effects, fewer than reported in most clinical trials. Dose reduction was required in 18% of patients. CONCLUSIONS: In a hospital clinic setting the effectiveness of interferon alfa-2b/ribavirin combination therapy appears equivalent to published results from clinical trials.