This paper looks at one treatment option for opioid addiction, namely, outpatient opioid replacement therapy. This involves not only medical treatment, but also embedding the replacement therapy in a comprehensive treatment plan. As part of this, the psychosocial care which social workers provide plays just as important a role as the care provided by medical staff. For this reason, the Bachelor’s thesis has two areas of focus. First, the paper goes into outpatient opioid replacement therapy and the legislation, requirements, procedure, and medication. The second focus is on the psychosocial care provided by social workers, which is to be seen as an accompanying measure. The theoretical foundations of psychosocial care are addressed such as the definition, procedure, the offers, and completion. The services currently offered in the federal state of Vienna will also be discussed in this paper. Finally, the paper looks at the importance of psychosocial care during outpatient opioid replacement therapy.