Abstract: New South Wales contains a large proportion of Australia’s estimated 200,000 to 300,000 injecting drug users (IDUs). This paper describes the development of NUAA (New South Wales Users and AIDS Association), an injecting drug users group, and the roles played by IDUs in the establishment and maintenance of NUAA’s services (Education Services, Community Services, Information/Tribes, and Needle Exchange/Referral) and NUAA Working Groups (Research, Newsletter Production, and HIV Support Group). The paper details the many ways in which IDUs (from both inside and outside the organisation) have become involved in NUAA, and how that involvement has changed as the organisation has grown. It also addresses the issues of professional behaviour by NUAA staff and the need for the organisation to be seen as credible at a governmental and policy making level to effectively represent the interests of IDUs while at the same time ensuring that it never becomes aloof from its constituency. The paper concludes with a set of recommendations for anyone interested in setting up an injecting drug users group for HIV prevention, education and advocacy.