The subject of the thesis is how drug users create identities in drug user unions. I am using a variety of theory inspired mostly by interactionism and partially by social movement theory on collective identity. I am using a broad dialectic sociological understanding of the concept identity, which unlike a psychological or a discursive approach is understood as an internal identification and an external recognition as being or belong with a specific group or category. The collective identity concept is being used relative to how groups can create an alternative identification by creating a boundary to negative social categories, which here is defined as the drug user category. The subject can relative to social work like “identity work” be seen as a contribution to understanding how this can be practiced without “professional” social workers. This perspective is relevant to studying how people who often are perceived as marginalized and being outside the mainstream of society collectively seek to create a different and more accepted identity. The focus is specific how drug users can create an identity in opposition to stigmatizing categories. I am focusing on a Danish drug user union “Danish Drug User Union” as an example on how identity as a drug user can be constructed in a specific context. The analytical focuses are on two levels an organizational and an individual member level. For this I have used qualitative empirical data like documents from the user unions’ website, an evaluation and an article about the organization as a whole plus interviewed member of the union for analysing the member level.