Conflict in marital relationships affects couple intimacy and satisfaction impacting on the couple system, the family system and wider social systems. Negative conflict is associated with breakdown in intimacy, marital dissatisfaction, and is seen to be a prominent cause of marital failure. As conflict is a process, it has the possibility of change and development over time, including moving towards a process whereby disagreements can be worked out with mutually acceptable solutions. Theoretical frameworks for conflict and marital counselling were reviewed and the systems-interactionist theory and a systemic-based counselling approach chosen for the purposes of this study. It was hypothesised that a systemic-based counselling approach would lower the levels of conflict occurring within a marital relationship. The principal objective of this study was to provide a more rigorous investigation than previous studies of client perceptions of the effectiveness of a systems-based counselling approach for marital counselling. Three case studies were conducted, with embedded units of analysis, within the context of a therapeutic process which drew on current theories of systemic counselling. Conflict was measured and operationalised as overt behavioural conflict, communication of negative affect, frequency of disagreements, intensity of disagreements, desire to change the other partner, the desire for change, and evidence of, and frequency of, positive conflict. As the study was based on the client's perceptions of change, multi-methods of selfreports were employed. As none of the known measurements met the needs of this study, a questionnaire known as the QCR was devised specifically for the pre- and posttests. The QCR was designed to measure: any increase or decrease in positive conflict; changes to both the intensity and frequency in negative conflict; and perceptions of the desire for change. The effectiveness of the counselling approach was measured by comparing the results of the pre-and post-tests with the continual self-reports and the self-reports at the long term follow-up interviews. An analysis of the self-reports focus on: the desire for change; the effectiveness of a systems based counselling approach in lowering negative conflict; and the usefulness of the QCR and other tools as measures. The systems-based-counselling approach, proved from the clients' perspective, to be: highly effective in case one; mostly effective in case two; and ineffective in case three as one partner aborted the counselling process. The systems-based-counselling approach had variable success in decreasing the intensity of negative conflict but was mostly successful in decreasing the frequency of negative conflict. This approach was not largely successful in reporting an increase in the frequency of positive conflict. The study revealed evidence of a relationship between commitment to the marital relationship and negative conflict. It also adds to the debate about the appropriateness of a systems-based counselling approach in violent relationships. In judging the clients' perceptions of the effectiveness of the systems-based counselling approach multi-measurements employed including the lengthy recording of the therapeutic sessions. It is claimed that this thesis offers a more rigorous methodology than anecdotal evidence previously used in the reporting of systemic counselling cases.