Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 16 1 2021 01 30 60 67 EN Zahra Pourmovahed Department of Nursing Education, Research Center for Nursing and Midwifery Care, Shahid Sadoughi University of Medical Sciences, Yazd, Iran AND Department of Health Education and Promotion, Social Determinants of Health Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Seyed Mojtaba Yassini Ardekani Department of Psychology, Research Center of Addiction and Behavioral Sciences, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Seyed Saied Mazloomy Mahmoodabad Department of Health Education and Promotion, Social Determinants of Health Research Center, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Hassan Zareei Mahmoodabadi Department of Education and Psychology, Yazd University, Yazd, Iran. 2018 08 09 Objective: Family function is one of the main effective factors on stability of the family. Family therapy can promote family function and performances. This study aimed to assess the effects of family therapy on family function among couples in Yazd province (Iran) based on the McMaster model. Method: The research population was selected from volunteer couples in Yazd in 2017 who were invited by publicity announcement to participate in this research. Finally, 40 couples were selected and randomly divided into 2 intervention and control groups. Participants responded to the demographic and Family Assessment Device (FAD) questionnaires. The obtained information was investigated using inferential and descriptive statistics and SPSS 21 software. Results: The results showed significant differences between the intervention and control groups in problem-solving (p = 0.01), communication (p < 0.0001), emotional responsiveness (p = 0.01), emotional involvement (p < 0.0001), and general function (p = 0.04). The roles and behavior control domains were improved after the intervention in 2 groups, but the differences were not significant. Conclusion: Family therapy based on McMaster model can promote the skills of problem- solving, family communication, emotional responsiveness, emotional involvement, and general function in couples. Healthy family functioning is an important domain of interest for mental health professionals who provide family interventions. Our findings add substantially to family professionals’ knowledge about patterns of family function in Iranian families. https://ijps.tums.ac.ir/index.php/ijps/article/view/1497 https://ijps.tums.ac.ir/index.php/ijps/article/download/1497/987