During a period of two years, nine patients were found who had a solitary geographic cluster of microcalcifications which appeared to be intramammary on two standard mammographic views. In two instances, the women underwent unsuccessful excisional biopsies. In the other seven patients, the true location of the microcalcifications was recognized and proved preoperatively so biopsy was avoided. When intradermal microcalcifications are fortuitously imaged in tangent or when they assume characteristic polygonal shapes with lucent centers, their intradermal location should be suspected. However, if the form is not typical of intradermal calcifications and when the location appears to be intramammary on the routine mammographic views, an excisional biopsy will usually be recommended. If skin is not included in the excised tissue, then the biopsy will be unsuccessful. A simple technique using a metallic marker can confirm the true intradermal location of calcifications.