The risk of exposure to hepatitis C virus increases markedly in adolescence, and students are thus a preferential target for information campaigns. The aim of this study was to evaluate the results of a hepatitis C information campaign targeting secondary-school students. The study was done in 52 classes of 11 general and vocational secondary schools. Before the information meetings and two months afterwards, the students received an anonymous questionnaire to test their knowledge of hepatitis C. The information session was backed up by a comic strip depicting scenarios involving hepatitis C. The students were aged from 14 to 24 years (mean 15.9 years, SD 0.9 years). Respectively 1509 and 1419 questionnaires were completed before and after the information session. Answers to the first questionnaire showed that the students' knowledge of hepatitis C was poor. Scores improved significantly after the information session, from an overall mean of 6.2 (SD 2.0) to 8.5 (SD 1.7) (p<0.001). The largest score improvement concerned transmission due to illicit drug use, the potential severity of the disease, and lack of a vaccine. The improvement was significantly larger among pupils who said they read the comic strip than among those who did not (p=0.02). General and vocational secondary school students in France have mediocre knowledge of hepatitis C, particularly its modes of transmission and the lack of a vaccine. Knowledge improved significantly when measured two months after an information session, suggesting that subsequent at-risk behaviours might be reduced.