The purpose of this study is to propose measures for social work practice to enhance the happiness of middle-aged married men and women by identifying the effects of family stress and social support resources (formal and informal support resources) on marital satisfaction among mid-life married couples. Subjects were selected through purposive sampling among married men and women aged between 40 and 59 and living in Seoul City and Gyeonggi province. The study results are follows. First, the average score of family stress was 3.06 points (SD=.56), slightly higher than the median value of 3 points. Of all subscales of family stress, the subjects experienced the most stress from family relationships, followed by financial problems, health and loss of families, and work-family compatibility. In regard to social support resources, the mean value of all social support resources categories was greater than the median. Among the subscales, informal support (family support and support from other people) was found to be higher than formal support. The level of marital satisfaction was higher than the median, and the score was 3.21 points (SD=.78). Second, in order to explore differences in marital satisfaction according to family stress and social support, differences in marital satisfaction were analyzed by grouping subjects who scored high, middle, and low levels of marital satisfaction. According to the results, marital satisfaction was statistically significantly higher in the group that experienced less family stress (F=6.25, p<.01). With respect to social support, marital satisfaction was statistically significantly higher in the group that received high social support (F=29.68, p<.001). Third, according to the analysis of factors affecting marital satisfaction in middle-aged married men and women, subjective economic status, family relationship stress, economic stress, and family support showed statistical significance. The higher the subjective economic status and the lower the family relationship stress and economic stress levels, the higher the marital satisfaction among middle-aged married men and women. In addition, the greater the family support, the higher the marital satisfaction. The results of this study underscore the need to improve family relationships in middle-aged married couples and to distribute family life education programs that can strengthen family support resources. For example, family relationship enhancement programs are currently performed, including "Family School for Middle-Aged Baby Boomers" and others as part of the Healthy Family Support Work regarding the promotion of marital satisfaction of middle-aged couples. In addition, continuing effort is warranted to include content on strengthening family support resources, maximizing the effectiveness of programs, and promoting service accessibility.