This study's goals were to examine coping strategies of women and their male partners as predictors of change in women's adjustment over the year following breast cancer treatment and to test whether partners' coping processes interact to predict adjustment. In a sample of women who had recently completed breast cancer treatment and were taking part in a psychoeducational intervention trial, the patients' and partners' cancer-specific coping strategies were assessed at study entry (average of 10 months after diagnosis). Assessed at study entry and 20 months after diagnosis (n = 139 couples), dependent variables were women's general (i.e., vitality, depressive symptoms, relationship satisfaction) and cancer-specific adjustment (i.e., cancer-specific distress, perceived benefits). Both patients' and partners' coping strategies at study entry predicted change in women's adjustment at 20 months. Women's use of approach-oriented coping strategies predicted improvement in their vitality and depressive symptoms, men's use of avoidant coping predicted declining marital satisfaction for wives, and men's approach-oriented strategies predicted an increase in women's perception of cancer-related benefits. Patients' and partners' coping strategies also interacted to predict adjustment, such that congruent coping strategy use generally predicted better adaptation than did dissimilar coping. Findings highlight the utility of examining patients' and partners' coping strategies simultaneously.