Background: Thalassaemia is a public health burden in Malaysia and its prevention faces many challenges. In this study, we aimed to assess the effectiveness of a web-based educational module in improving knowledge and attitudes about thalassaemia prevention amongst Malaysian young adults. Methods: We designed an interactive web-based educational module in the Malay language wherein videos were combined with text and pictorial visual cues. Malaysians aged 18-40 years old who underwent the module had their knowledge and attitudes assessed at baseline, post-intervention and at 6-month follow-up using a selfadministered validated questionnaire. Results: Sixty-five participants: 47 Malays (72.3%), 15 Chinese (23.1%), three Indians (4.6%) underwent the module. Questionnaires were completed at baseline (n=65), postintervention (n=65) and at 6-month follow-up (n=60). Out of a total knowledge score of 21, significant changes were recorded across three time-points- median scores were 12 at pre-intervention, 19 at post-intervention and 16 at 6-month follow-up (p<0.001). Post-hoc testing comparing preintervention and 6-month follow-up scores showed significant retention of knowledge (p<0.001). Compared to baseline, attitudes at 6-month follow-up showed an increased acceptance for “marriage avoidance between carriers” (pre-intervention 20%, 6-month follow-up 48.3%, p<0.001) and “prenatal diagnosis” (pre-intervention 73.8%, 6-month follow-up 86.2%, p=0.008). Acceptance for selective termination however, remained low without significant change (pre-intervention 6.2%, 6-month follow-up 16.7%, p=0.109). Conclusion: A web-based educational module appears effective in improving knowledge and attitudes towards thalassaemia prevention and its incorporation in thalassaemia prevention programs is potentially useful in Malaysia and countries with a high internet penetration rate.