In the field of family counseling and psychology, various approaches have been developed to reduce conflicts and communication disorders between couples. The aim of this study was to compare the effectiveness of McMaster and Nichols family counseling approaches on problem solving ability. The present study is an applied research in terms of purpose and a quasi-experimental study in terms of method with pre-test-post-test design and control group. The study population consisted of all couples referring to counseling centers in Boroujerd in 2020- 2021, from which 36 couples with marital incompatibility were selected as a sample. The tools of the present study included the Family Problem Solving Questionnaire (FPS) (1989). McMaster family therapy intervention was performed in 10 sessions of 1.5 hours and Nickels family therapy in 12 sessions of 1.5 hours each one week; But the control group did not receive any intervention. The research data were analyzed by mixed analysis of variance (with repeated measures). Findings showed that McMaster's family therapy and Nichols's family therapy are effective on problem solving ability in couples (P <0.05). The results also showed that there was no difference between the effectiveness of McMaster's family therapy and Nichols family therapy interventions in adaptation (p <0.05). It can be concluded that McMaster's family therapy and Nichols's family therapy are effective in adapting the couple.
