OBJECTIVES: The objectives of this study were to identify and quantify the factors driving patient and physician preferences for treatments of genotype 1 hepatitis C virus infection in the UK. METHODS: A web survey was conducted, including 100 patients (50 treatment-naive and 50 treatment-experienced patients) and 50 physicians (gastroenterologists/ hepatologists and infectious disease specialists). A discrete-choice experiment was conducted to elicit the participants’ preferences on the basis of seven attributes with four levels each: efficacy, that is probability of reaching sustained virologic response, treatment duration, treatment convenience (i.e. number of pills and/or injections), gastrointestinal problems, anaemia, dermatological problems and neuropsychological problems. The statistical analysis applied a mixed logit model to estimate preference weights and relative importance scores. RESULTS: Results indicated that the sustained virologic response rate was the most important attribute to participants. Physicians placed an even greater weight on the efficacy of treatments with a relative importance score of 9.33 [95% confidence interval: (6.93-11.91)], as compared with 6.16 [95% confidence interval: (4.34-8.15)] for patients. Neuropsychological problems ranked second for patients and physicians, and were more important to treatment-naive patients than to treatment-experienced patients or physicians. Gastrointestinal problems, anaemia and dermatological problems were of minor importance to all participants. These findings may be explained by the improvement in the management of physical adverse reactions over the last few years, thus making treatment easier to tolerate. CONCLUSIONS: This study is the first conjoint analysis assessing and comparing the preferences of patients and physicians in hepatitis C virus.