The purpose of this study was to isolate breast size as a potential risk factor for breast cancer. 101 complete patient records were collected in a case control study to measure factors, including breast volume of each breast. Of these, 54 had a known cancer and 47 were normal controls. The breast cancer patients were taken from the Cleveland Clinic breast cancer registry and the controls were taken from patients receiving screening mammograms. Two doctors independently measured the height and radius of each breast from the mammogram in the craniocaudal view, and then calculated the volume. If variation in the measurement was greater than 10%, a third measurement would be taken to verify accuracy. We identified age, weight, and height as confounding factors and analyzed their effects using a logistic regression. Our preliminary results show that larger breasted women are more likely to incur breast cancer after adjusting for height and weight. Our conclusion is that breast size is an independent risk factor for breast cancer.