The purpose of this essay is to explore the significance for former drug addicts who, during their treatment against drug abuse, have had a therapist with a drug addiction in his or her past. A qualitative case study has been used as method in which four former drug users have been interviewed. We have compiled the results based on five key themes in order to get a comprehensive picture of the relevance of common experiences regarding drug abuse, based on former addicts’ experiences. This has been done in connection with a review of different theoretical perspectives that we have found relevant to the investigation. Our findings have then been compared with previous research in the field. We have, in our investigation, come to the conclusion that the therapist’s and the drug addict’s mutual experience of drug abuse regarding drug addiction treatment, is that it is not important. However, there are aspects concerning the relation between drug users and their therapists in which the mutual experience is important.