The frequency of benign mammary disease and the need to differentiate between benign and malignant tumors without the indiscriminate use of instrumental examinations and biopsies have prompted the Cooperative Interdisciplinary Group on Mammary Neoplasms to adopt the diagnostic protocol and propose a number of therapeutic indications. Though involving a progressive reduction in biopsies, the use of the protocol has not led to failure to recognize carcinomas, the number of identified malignancies being maintained within the anticipated limits.