This study examined mood disturbance among women with metastatic breast cancer in relationship to partnership status, relationship quality, and partner's coping and mood disturbance. These associations were examined within a total sample of 125 metastatic breast cancer patients and a subsample of 48 of these patients and their partners. Partnered and single women were indistinguishable in mood disturbance when household income was statistically controlled. Results also showed that patients were less distressed when they rated the relationship higher in Cohesion--Expression and in Conflict and when their partners reported lower mood disturbance. One possible implication of these results is that in relationships in which a woman has metastatic cancer, she may benefit from open engagement of difficulties and conflict. Furthermore, alleviating her distress may be better achieved by focus on the couple relationship rather than her individual coping.