Using a sample of 322 married couples (644 spouses) from The Flourishing Families project, this study examined the relationship between marital power and sexual satisfaction as mediated by observed hostile interaction. More specifically, an actor-partner interdependence model (APIM) was used in which husband and wife perceptions of their partner's power were hypothesized to be related to husband and wife self-report of sexual satisfaction, with husband and wife observed hostile interaction as possible mediating variables. Results showed that husband and wife perceptions of power were positively related to their respective husband and wife sexual satisfaction and positively related to their respective hostile interaction. Husband hostile interaction was negatively related to husband sexual satisfaction. Husband and wife perceptions of power were negatively related to their partner's sexual satisfaction, and positively related to their partner's hostile interaction. Husband and wife hostile interaction were negatively related to their partner's sexual satisfaction. Husband observed hostility was a statistically significant mediator of the relationship between husband power and husband sexual satisfaction and of the relationship between wife power and wife sexual satisfaction. Wife observed hostility significantly mediated the relationship between husband power and husband sexual satisfaction.