ABSTRACT Most of what is now known about the causes of marital distress and divorce is based on either demographic data or on the recollections of formerly married spouses. Demographic data provide little insight into what it is about spousal qualities and the stresses that couples confront that leads to unhappiness and divorce. Recollections can be distorted as a consequence of the experiences associated with the divorce process. This research will use longitudinal data covering the first twelve years of the marital experience to overcome these handicaps. This research seeks to determine the connection between the social and psychological characteristics partners bring to marriage, the early years of their marriage, and the cohesion and stability of their union over twelve years. Data gathered between 1981 and 1983 will be supplemented with new data on parenting and on economic hardship to predict more than twelve years after couples were wed: (a) the stability of their marriage (married vs. divorced); (b) the length of time (in months) their marriage lasted; and (c) their level of marital satisfaction (for those still married). Changes in levels of compatibility also will be examined in regard to preferences in leisure activities and household work. The investigation extends a large-scale social psychology study on courtship and the early years of marriage into a long-term prospective study of the causes of dissatisfaction and divorce. It represents the first effort to trace over time the evolution of relationships that develop distress or end in divorce. The study should be valuable for marriage counselors working with couples either contemplating marriage or already married and should provide a firmer and deeper theoretical and substantive understanding of marital relations, in particular, and human relationships, more generally.