This study has confirmed that initiation to heroin use in Australia typically occurs via injection, though this is less apparent among younger heroin uses. The study has also found that more than a third of heroin users have initiated others into injecting, with close to a fifth having done so recently. Many of those who engaged in this behaviour tended to take greater injection related risks which has important implications for the transmission of blood-borne infections. A better understanding of the circumstances surrounding the initiation to heroin injection is needed. Peer-led interventions, which have been found to be effective in changing IDUs' attitudes and behaviours [26], may have a role to play in reducing the number of heroin users initiating others to injecting.