• Fifty-six married inpatients with primary affective disorders and their spouses participated in a 12- to 36-month followup study in which the relationship of assortative mating to social adjustment and course of illness was examined. At follow-up, the patients who were concordant with their spouses for psychiatric illness had poorer social adjustment than the group of patients with well spouses. This finding was confirmed by both relatives' ratings and clinicians' ratings of the patients' social adjustment. Measures of relapse since the target hospitalization and self-rated symptoms at the time of follow-up were not different for the two groups. The divorce rate, however, was significantly greater for the couples who were concordant for psychiatric illness when compared with the discordant couples.