Abstract : This case control study examines breast cancer risk in relation to lifetime alcohol consumption. Subjects are 335 white and 35 black pre-menopausal and 900 white and 80 black postmenopausal women, age 35 to 79, from Erie and Niagara counties in western New York State, with incident, pathologically confirmed breast cancer. Controls are randomly selected and are frequency matched to cases on age, race and county of residence. Subjects receive a computerized interview which focuses on aspects of alcohol consumption such as frequency, quantity per occasion, beverage type, and drinking pattern through the life span. Important potential confounding factors such as reproductive and medical history, family history of disease, diet, exercise, smoking, passive smoking, occupation, residential history, and anthropometric measures and demographics are also assessed. A specimen bank is used to store biological samples for future research in relation to serum and urinary markers including hormones in serum, hormone metabolites in urine, serum and erythrocyte folate levels, blood levels of antioxidants, blood measures of oxidative status, and genetic polymorphism in carcinogen metabolism. This study provides an important opportunity for an efficient examination of alcohol and other risk factors, particularly genetic variability, in relation to breast cancer risk, with potential for clarification of a significant public health problem.