This study focused on the relationship of objective and subjective stresses to survival from breast cancer. The potential mediating roles of social support and age were also considered. This prospective study involved 208 white female breast cancer patients diagnosed between 1958 and 1960. At the time of diagnosis, subjects were interviewed regarding objective and subjective stress and social support present in the 5-year period preceding their diagnosis. Twenty years later, survival was calculated. The relationships between stress and survival were examined for three age groups: 15–45, 46–60, and 61 and older. Objective stress was related to survival for the oldest group while subjective stress was related to survival for the youngest group. Neither stress was related to survival for women aged 46–60. Social involvement was independently related to survival although it was not a mediator in the stress-survival relationship. Using the entire sample, stage of cancer at diagnosis was the best predictor of survival. However, when women aged 46–60 were eliminated from the analysis, stress and social involvement accounted for twice as much variance in survival as stage.