Fingerprints and palm prints were studied in 78 breast cancer patients, 391 patients at increased risk for developing breast cancer, and 64 control patients for the purpose of finding a pattern that would identify those women with breast cancer or those who are predisposed to its development. A pattern of 6 or more digital whorls was identified more frequently in women with breast cancer than in those without the disease (P less than 0.01). This finding was independent of known risk factors for breast cancer and was present in 28% of the cancer patients. No correlation was noticed between palm prints and breast cancer. The positive predictive value of 6 or more digital whorls was comparable to that of mammography and that of breast biopsy. With increasing age there was an increase in the positive predictive value associated with 6 or more digital whorls. It is concluded that digital dermatoglyphics may have a future role in identifying women either with or at increased risk for breast cancer such that either risk reduction measures or earlier therapy may be instituted.