Introduction: Research has shown that orthodontic patients are more likely to retain information presented in an audiovisual format. However, there has been little research on the effectiveness of audiovisual information provided through different routes such as the Internet. This parallel-group randomized controlled trial assessed whether provision of audiovisual information on the YouTube (Google, San Bruno, Calif) Web site to orthodontic patients undergoing fixed appliance treatment results in improved patient knowledge when compared with conventional methods of information provision. The effects of sex and ethnicity were also investigated.