From 1963 to 1973 at Emory Clinic 17,288 breast examinations, including history, physical examination, and mammography, were performed on 6342 patients. The resulting 2793 breast biopsies included 2056 benign and 737 malignant lesions. High-risk and low-risk groups of breast cancer patients were observed for presence or absence of a mass or masses clinically and by roentgenograph, age, and breast pathology. The breast biopsy rate was the same for all age groups studied. The percentage of cancer per biopsy varied from 0 to 100 when the various combinations of mass (masses), no mass, and age were considered. Low priority (less than 5% cancer) groups were: in all age groups no mass by roentgenograph or clinically and no mass by roentgenograph and clinical multiple masses; for the 0-32 age group, all categories except single mass by roentgenograph and clinically; and for the 0-38 age group all categories except mass or masses both by roentgenograph and clinically. Using this wide range in the ratios of cancer, priority for biopsy can be established for each group. The surgeon can use additional clinical assessment of relative risk to contribute to a n increased priority scheme.