Supervision is a mandatory requirement of counsellors for the duration of their professional lives and is established as an essential aspect of counselling practice. The aim of this study is to examine the role of clinical supervision as a resource towards an effective therapeutic relationship in the Northern Area Health Board Addiction Services. The study examines the influence of institutional factors on supervision and the effectiveness of supervision if based on a particular model. The function of clinical supervision in understanding the difference between personal process and personal therapy is discussed. Forty questionnaires in total were circulated to a sample group of twenty eight counsellors and twelve clinical supervisors. Twenty nine questionnaires in total were returned. Results show that both sample groups are in agreement that clinical supervision improves the effectiveness of counselling and that institutional factors effect the supervisory relationship. Supervisors and counsellors differed in their perception of lines of responsibility and accountability indicating uncertainty by counsellors about the role of supervision. Research on beliefs and practices essential to the practice of therapy and supervision highlighted areas of agreement and some diversity of views from both sample groups. These views indicate some perceptual differences by counsellors of the role of supervision. The main findings show support to the concept of lifelong supervision and highlight the extent to which the medical model predominates in substance misuse programmes. Counsellors discuss the benefit of supervision in terms of bringing another perspective on client issues and express some reservations about the role of external supervision and the ability to empathize with the experience of working in the area of substance misuse.