ObjectivesThe rate of organ donation in Hong Kong is among the lowest in developed regions. Since medical students will play an important role in counselling patients for organ donation and identifying potential donors in the future, their knowledge, attitudes and action for organ donation are important. This study aims to understand knowledge, attitudes and actions with regard to organ donation among medical students and investigate the factors determining the knowledge and attitudes.DesignA cross-sectional study.Setting and participantsMedical students in Hong Kong were invited to complete a questionnaire. 377 medical students participated in the study.MethodsThe questionnaire assessed their attitudes, knowledge, action of organ donation, belief and perception on organ donation, and other factors. Linear regression analyses and logistic regression were performed to analyse the effect of the variables on knowledge, attitudes and action for organ donation.ResultsAlmost all medical students (99.5%) held a positive attitude towards organ donation, but only 28.1% have signed up as organ donors. Determinants of knowledge of organ donation included belief in preservation of intact body after death (β = –0.14, 95% CI = –0.24 to –0.04) and perceived confidence and competence of organ donation discussion (β = –0.12, 95% CI = –0.22 to –0.02). Predictors of organ donor registration status included knowledge of organ donation (OR=1.03, 95% CI=1.00 to 1.06), perceived convenience of organ donation registration (OR=3.75, 95% CI=1.62 to 8.71), commitment to organ donation (OR=3.81, 95% CI=2.01 to 7.21) and exposure to organ donation (OR=4.28, 95% CI=2.37 to 7.74).ConclusionsKnowledge is positively associated with organ donation action. The above determinants of organ donation could be emphasised in medical education.