Non-adherence to treatment is a major problem faced by professionals in mental health-care. Non-adherence to treatment increases the costs of service, in financial terms, as well as in the investment of time and effort. In addition, research has shown that outcomes of service may be negatively affected as a result of non-adherence. One factor that has been found to increase adherence to treatment programs is commitment. The purpose of the present study is to examine the efficacy of an intervention designed to increase adherence to treatment by increasing client commitment to therapy. This intervention is based on Rusbult's Investment Model of commitment. The participants in this study were 6 clients being seen at a university psychological services center. A multiple baseline across subjects design was used to analyze the efficacy of this treatment. It was found that only two of the six subjects met criteria for success in this intervention. However, in five of the six subjects, adherence to treatment increased when seen from a more long-term perspective. No difference in satisfaction with therapy was found between the subjects who successfully completed the treatment and those who did not successfully complete the treatment. Other elements of the treatment, such as participant demographics, treatment outcome, and presenting problems were analyzed descriptively. The results indicate that this intervention is insufficient to address the problem of non-adherence to therapy. Explanations regarding the failure of this intervention are discussed.