Increasingly, prison drug treatment is introduced in European prisons. This increase may begin to change the prison as officers and drug counsellors are given new occupational responsibilities. Based on six month of observational studies and qualitative interviews with 104 prison employees in Denmark, Sweden, Finland and Norway in 12 prisons, this article investigates the practices and values of drug counsellors and officers. This shows that increasingly, counsellors integrate the control and disciplinary sanctions of the prison environment into their treatment approach. Simultaneously, officers working in drug treatment wings highlight the importance of the treatment ethos in their control work, adjusting the social representations of their professional identities accordingly. We discuss whether the concepts of treatment and control should be rethought.