Objective: To investigate the hypothesis that alcohol consumption increases the risk of breast cancer mortality. Methods: We examined breast cancer mortality in relation to self-reported alcohol consumption in women from the American Cancer Society Cancer Prevention Study (CPS)-II. After 14 years of follow-up, 1,442 eligible breast cancer deaths were observed among 242,010 women. Cox proportional hazards models were constructed for total alcohol consumption and for beer, wine, and liquor separately. Results: Total alcohol consumption was associated with increased risk of fatal breast cancer among post- but not pre- or perimenopausal women. Even less than one drink/day was associated with up to a 30% increase in breast cancer mortality among postmenopausal women compared to non-drinkers (RR = 1.3, 95% CI: 1.1–1.6 for women drinking 0.26–<1 drink/day).="" when="" examined="" separately,="" consumption="" of="" beer,="" wine,="" and="" liquor="" each="" increased="" the="" risk="" of="" breast="" cancer="" among="" postmenopausal="" women.="" we="" found="" no="" evidence="" that="" alcohol="" consumption="" was="" more="" deleterious="" among="" women="" at="" high="" risk="" for="" breast="" cancer="" compared="" to="" average-risk="" women.="">Conclusion: This study adds to the evidence that postmenopausal women can reduce their risk of breast cancer by avoiding or minimizing their use of alcohol.