Background and objective: Research about initiation to injecting drugs emphasises the role that relationships with others plays in the experience, suggesting investigations of initiation should include an examination of both initiates and initiators. However, available information about initiation tends to focus on the experience of the initiate and not the initiator. This paper describes the socio-demographic characteristics, drug and injecting practices, and harm reduction knowledge and practices of people who report initiating others to injecting. Method: Cross-sectional survey data from 324 young, early-career IDU was used to calculate and describe the number of other people initiated by initiators. Comparisons between initiators and non-initiators were made using logistic regression. Results: Fifty-five participants (17%) reported giving someone else their first injection. They reported initiating a total of 128 other people within the first 5 years of their own injecting. Compared to non-initiators, initiators were more likely to pass on harm reduction information (OR 2.36, 95%CI: 1.26-4.40). However, the content and quality of the harm reduction information was unknown. Initiators did not have more accurate knowledge of blood borne viruses than non-initiators, and commonly obtained needles and syringes from sources where the sterility of the equipment could not be guaranteed. Conclusions: This analysis shows that young, early-career IDU commonly initiate others to injecting. Intervention strategies aimed at reducing initiation should include young users and consider supporting them to increase their harm reduction knowledge and practices so that this can be passed on to initiates.