Peer-based outreach is a popular strategy in which former or current drug addicts are employed as peer educators to contact and educate out-of-treatment addicts. This study examines the interaction patterns that occur during outreach with particular regard to the roles that peer educators perform. Using ethnographic methods, it reports findings from a group of 'peer educators' and 'clients' from Yamuna Bazaar, New Delhi. In this context, peer educators assumed three roles that were co-constructed with clients: 'counsellor', 'doctor', and 'role model'. Analysis of these role-plays revealed three significant patterns. First, the performances involved a hierarchical structuring with the peer educator in an authority position in nearly all interactions. Second, the role-plays were fluid and evolving with peer educators often transitioning across roles during the same interaction. Lastly, role performances appeared to have an underlying role replication mechanism in which roles were learned by first playing the subordinate role (e.g. 'patient') and then performing the dominant role (e.g. 'doctor') with another peer (e.g. new 'patient'). These findings provide insight into issues of empowerment, peer relationship dynamics, and social diffusion processes among drug-using communities, and peer-based situations more generally.