Background Knowledge and attitude towards organ donation are critical factors influencing organ donation rate. We aimed to assess the knowledge and attitude towards organ donation in adolescents in Austria and Switzerland. Methods A paper-based survey was performed in two secondary schools in Austria and Switzerland. 354/400 surveys were sufficiently answered and analyzed. Results Our study found that knowledge on organ donation is scarce in adolescents. Less than 60% of those surveyed thinks that a person is dead when declared brain dead. (...) 84.6% would authorize organ donation after brain death for themselves, but only 69% would authorize organ donation after brain death for a close relative. 93.7% would accept a donor organ if they needed one. Family discussions, rather than school discussions, influenced knowledge on organ donation, the percentage of respondents who have a firm opinion on organ donation and the rate of declaration of this opinion. Age, gender, nationality and religion also influenced knowledge and attitude towards organ donation. Nearly one third of adolescents are of the opinion that selling non-vital organs should be legalized. Conclusion Since having had family discussions, a potentially modifiable factor, was positively associated with knowledge and attitude towards organ donation, we postulate that educational programs stimulating family discussions on organ donation may be a promising strategy to increase knowledge. (shrink)