Although the field of couple therapy has made significant strides in recent years, there continues to be a need for theoretically sound and empirically supported treatments. The current case study examines whether Acceptance and Commitment Therapy (ACT), an experiential acceptance-based behavior therapy, can be effective in treating distressed couples. Although ACT has demonstrated effectiveness in treating a variety of disorders in individuals, it has not been systemically applied to the treatment of couple distress, and the current study is the first empirical examination of ACT for the treatment of couples. Two married couples participated in the study. A number of core ACT interventions were modified to treat couples in a conjoint format. Cognitive defusion exercises were used to help couples reduce their fusion with and the believability of negative thoughts and feelings related to the relationship. Mindfulness and acceptance techniques were used to help couples increase awareness of their reactions to negative relationship cycles. Finally, value-directed action was used to help partners act in ways consistent with relationship values even in the presence of unwanted thoughts and feelings. The results of this preliminary case study suggest that ACT may be effective in increasing marital adjustment and satisfaction, and in reducing interpersonal and psychological distress in couples. Future studies with larger samples and more controlled designs are needed to build on the results from this single-case study. (Contains 2 tables and 4 figures.)