The purpose of this study was to explore whether stress from individual's and partner's depression, anxiety, sleep disturbances, insecure attachment and meaning in life were predictors of diurnal cortisol patterns in breast cancer survivors and their spouses. Thirty-four couple dyads participated in this eight-month follow-up study. The breast cancer survivors and their spouses completed the Medical Outcomes Study Sleep scale, the Beck Depression Inventory-II, the State Trait Anxiety Inventory, the Experiences in Close Relationships-Revised scale and the Meaning in Life Questionnaire, and they collected salivary cortisol at home at the time of awakening, 30 and 45 min after waking and at 1200 h, 1700 h and 2100 h. Diurnal cortisol slopes of survivors and spouses are positively correlated. But the factors associated with diurnal cortisol patterns are different between survivors and spouses. For survivors, neither survivor individuals' nor spouses' psychosocial factors were the predictors of survivors' diurnal cortisol patterns. For spouses, the survivors' higher anxious attachment style was the main predictor of spouses' flatter diurnal cortisol patterns. In conclusion, for spouses, psychophysiological stress responses are mainly influenced by breast cancer survivors' insecure attachment. Future couple supportive care interventions can address survivors' attachment styles in close relationships in order to improve neuroendocrine functions for both breast cancer survivors and their spouses.