Terfenadine (4-[4-(hydroxydiphenylmethyl)-1-piperidyl]-1-(4-tert-butylphenyl)-butan-1-ol) was identified in a biological screening to be a moderate inhibitor (27% inhibition) of the CD81-LEL–HCV-E2 interaction. To increase the observed biologicalactivity, 63 terfenadine derivates were synthesized via microwave assisted nucleophilicsubstitution. The prepared compounds were tested for their inhibitory potency by means ofa fluorescence labeled antibody assay using HUH7.5 cells. Distinct structure-activityrelationships could be derived. Optimization was successful, leading to 3g, identfied as themost potent compound (69 % inhibition). Experiments with viral particles revealed thatthere might be additional HCV infection reducing mechanisms.