In this 10-year longitudinal study, long-term relationship satisfaction and stability were predicted from communication behavior, stress level, physical and psychological well-being, and individual and dyadic coping skills. The predictors were assessed at the beginning of the study. Significant predictors of relationship satisfaction (n = 103 couples) for both men and women were relationship satisfaction in the beginning, and for men additionally their dyadic coping competencies. Significant predictors of relationship stability (N = 162 couples) were relationship length, relationship satisfaction of both men and women, as well as women’s positive communication. The percentage of correct classifications (stable or unstable relationship) over a period of 10 years was 80.3%. Implications for research and prevention as well as the importance of coping skills for relationship outcome are discussed.