Aim: Young people who are socially engaged with people who inject drugs are at higher risk of transitioning to injecting drug use. We aimed to examine rates of exposure to injecting among young people in an online survey, and whether exposure to injecting was related to hepatitis C(HCV) knowledge. Methods: A cross-sectional, online survey was completed by 827 young people (aged 16-26 years) in New South Wales, Australia. Exposure to injecting in the preceding 12 months was measured by asking participants whether close friends and romantic/sexual partners had injected, and whether somebody had offered them an injection. HCV knowledge was measured using items adapted from a survey of Australian secondary school students. Findings: Eleven percent of participants reported recent exposure to injecting.Participants exposed to injecting were significantly more likely than other participants to report use of injectable drugs. Some aspects of HCV transmission were poorly understood, and exposure to injecting was not significantly associated with higher HCV knowledge. Conclusions: While online methods were only moderately successful in recruiting people exposed to injecting, higher rates of use of injectable drugs and HCV knowledge deficits in this group suggests that they are an important target for HCV education and prevention.