In a consecutive series, clustered breast calcifications were classified according to their radiographic appearance. Rounded and 'cloudy' calcifications, and calcifications showing sedimentation were virtually always associated with benign disorders. All other types of clustered calcifications implied a substantial risk of carcinoma. Furthermore, calcifications appearing or increasing during an observation period (median 24 months) implied a larger risk than those remaining unchanged. Guidelines for the management of patients with clustered breast calcifications are given.