Current evidence supports the effectiveness of behavioural methods in the treatment of trichotillomania (compulsive hair-pulling). In particular, the Habit Reversal Method has been demonstrated to be effective. Some discussion has centred on defining the active components of this “package” and whether it is applicable to all clients. This case study reports on the successful use of the method to treat a 19-year-old female. Treatment produced an immediate reduction in the number of hairs pulled out, although the client relapsed. Functional analysis was unable to detect any factors associated with this other than loss of client-therapist contact, and the re-introduction of treatment with an emphasis on client self-reinforcement for progress produced significant improvement. This continued upon withdrawal of treatment and was maintained at a follow-up 6 months later. In addition, the intervention resulted in the client being able to exhibit increased control over the behavioural chain which culminated in hairs being extracted. A relationship appeared to exist between these two forms of behaviour change. The findings were discussed with regard to the proposed active change agents in the treatment of trichotillomania.