Introduction and Aims. Young people are at high risk of alcohol-related harm and injury. This study assessed awareness of the 2009 Australian Guidelines to Reduce Health Risks from Drinking Alcohol, understanding of alcohol-related risks and drinking behaviours among young people. Design and Methods. We recruited participants (16-29 years) from a music festival in Melbourne, Australia, January 2010. Participants self-completed a risk behaviour questionnaire which included questions regarding the 2009 guidelines. Characteristics associated with awareness of the guidelines and accurate understanding of a ‘safe’ number of drinks to avoid long-term harm and injury (defined as a maximum of two drinks daily and four drinks on a single occasion, respectively) were examined using multivariable logistic regression. Results. Of 1381 participants, only 32% were aware of the 2009 guidelines, but the majority had an accurate understanding of the safe number of drinks to avoid long-term harm (74%) and injury (71%). Nonetheless, many reported drinking behaviour with risk of long-term harm (22%) or injury (54%). Participants with lower-risk drinking behaviours were more likely to have an accurate understanding of the safe number of drinks to avoid harm. Males and participants without post-high school education were significantly less likely to be aware of the guidelines and/or have an accurate understanding of alcohol-related risks (P < 0.05). Discussion and Conclusions. Although raising awareness of alcohol-related risks may promote reduced alcohol consumption, many young people reported consuming alcohol at harmful levels despite having an accurate understanding of alcohol-related risks. Multiple approaches to reducing alcohol-related harm in young people should be considered.[Bowring AL, Gold J, Dietze P, Gouillou M, van Gemert C, Hellard ME. Know your limits: Awareness of the 2009 Australian alcohol guidelines among young people. Drug Alcohol Rev 2012;31:213-223].