Objectives: The purpose of this study was to examine the actor and the partner effects in the process of which mindfulness affected marital satisfaction through communication among middle-aged couples. Methods: 309 couples aged 40~65 residing in Seoul, Gyeonggi, Incheon, and Daejeon participated. The data were analyzed using the Actor-Partner Interdependence Model (APIM). Results: First, while there was no significant difference between the husband’s and wife’s mindfulness, the wives had higher communication ability, and the husbands had higher marital satisfaction. Second, it was found that the higher one’s mindfulness, the higher one’s own communication. The higher the husband’s mindfulness, the higher the wife’s communication, but the wife’s mindfulness did not affect the husband’s communication. Third, it was found that the higher one’s communication, the higher the one’s own marital satisfaction as well as the partner’s marital satisfaction. Fourth, there were significant mediation effects between the husband’s and wife’s mindfulness and their own and the partner’s marital satisfaction through one’s own communication. Conclusions: The implications for the practice of marital therapy and future research based on the study results were discussed.