ObjectiveObtaining informed consent is a cornerstone requirement of conducting ethical research. Traditional paper-based consent is often excessively lengthy and may fail to achieve the desired participant understanding of study requirements. Multimedia tools including video and audio may be a useful alternative. This study aimed to determine the efficacy, usability and acceptability of self-directed multimedia delivery of participant consent.DesignIt is a single-centre, randomised, prospective study to determine the efficacy, usability and acceptability of a self-directed multimedia consent process (intervention) compared with the traditional paper-based approach (control). The intervention was free of research staff, with computer-based finger-signed consent.SettingPathology blood collection services in Tasmania, Australia.Participants298 participants (63±8 years; 51% female individuals) referred from general practice were randomised to intervention (n=146) and control (n=152).Outcome measuresEfficacy, usability and acceptability of the allocated consent process were assessed by a questionnaire.ResultsAll participants successfully completed the allocated interventions. Efficacy parameters were higher among intervention participants, including a better understanding of study requirements compared with controls (p<0.05 all). Intervention participants were more likely to engage with the study information and spend more time on the consent process (p=<0.001 and p=0.006, respectively). Both groups reported similar levels of acceptability, although more control participants reported that the study information was too long (24% vs 14%; p=0.020).ConclusionA self-directed multimedia consent process is effective for achieving participant understanding and obtaining consent free of research staff. Thus, multimedia represents a viable method to reduce the burden on researchers, meet participant needs and achieve informed consent in clinical research.